Handbook Tech Standar Tv Production

ITC Handbook of Technical Standards for Television Programme Production Issue 2.0-December 1996

I T C

HANDBOOK OF TECHNICAL STANDARDS

FOR

TELEVISION PROGRAMME PRODUCTION

PART A

ISSUE 2.0 - DECEMBER 1996

Standards and Technology, Engineering Division,Independent Television Commission,

Kings Worthy Court, Kings Worthy, Winchester, Hants SO23 7QA

Contents & Introduction On-line version source EBU website

ITC Handbook of Technical Standards for Television Programme Production Issue 2.0 December 1996II

Independent Television Commission, 1992, 1993 and 1996.

All rights reserved. No reproduction, copy or transmission of this publication may be made without thewritten permission of the Independent Television Commission.


ITC Handbook of Technical Standards for Television Programme Production Issue 2.0 December 1996 III

HANDBOOK OF TECHNICAL STANDARDS

PART A: STUDIO CENTRES AND OUTSIDE BROADCAST FACILITIES

CONTENTS

CONTENTS III

INTRODUCTION VITechnical Performance Working Party Membership VIPast Membership VI

SECTION 1 VIDEO CIRCUITS AND EQUIPMENT WITHIN THE SIGNAL PATH 11.1 PERFORMANCE FIGURES (COMPOSITE PATHS) 11.2 RECOMMENDED TEST METHODS (COMPOSITE PATHS) 31.3 PERFORMANCE FIGURES (COMPONENT PATHS) 81.4 RECOMMENDED TEST METHODS (COMPONENT PATHS) 9

SECTION 2 AUDIO CIRCUITS AND EQUIPMENT WITHIN THE SIGNAL PATH 132.1. PERFORMANCE FIGURES 132.2 RECOMMENDED TEST METHODS 15

SECTION 3 VIDEO TAPE RECORDERS 193.1. PERFORMANCE FIGURES (COMPOSITE RECORDERS) 193.2. RECOMMENDED TEST METHODS (COMPOSITE RECORDERS) 21VIDEO MEASUREMENTS 21AUDIO MEASUREMENTS 233.3 PERFORMANCE FIGURES (COMPONENT RECORDERS) 253.4 RECOMMENDED TEST METHODS (COMPONENT RECORDERS) 26

SECTION 4 AUDIO RECORDERS 314.1. PERFORMANCE FIGURES 314.2. RECOMMENDED TEST METHODS 32

SECTION 5 CAMERAS 355.1. PERFORMANCE FIGURES 355.2 RECOMMENDED TEST METHODS 36

SECTION 6 TELECINES AND SOUND FOLLOWERS 436.1. PERFORMANCE FIGURES 43VIDEO TOLERANCES 43AUDIO TOLERANCE 456.2 RECOMMENDED TEST METHODS 46VIDEO MEASUREMENTS 46

SECTION 7 DISC REPRODUCERS 557.1. PERFORMANCE FIGURES 55


ITC Handbook of Technical Standards for Television Programme Production Issue 2.0 December 1996IV

7.2 RECOMMENDED TEST METHODS 56

SECTION 8 WAVEFORMS 598.1 SOUND-IN-SYNCS 59

Fig 8.1 - Sound-in-Syncs Signal 598.2 VERTICAL BLANKING INTERVAL 59

SECTION 9 PEAK PROGRAMME METERS 639.1 PERFORMANCE FIGURES 639.2 RECOMMENDED TEST METHODS 64

SECTION 10 SATELLITE LINKS PATHS 6710.1 PERFORMANCE FIGURES (Vision) 6710.2 RECOMMENDED TEST METHODS (Vision) 6910.3 PERFORMANCE FIGURES (Sound) 7410.4 RECOMMENDED TEST METHODS (Sound) 75

SECTION 11 DIGITAL VIDEO CIRCUITS AND EQUIPMENT 7711.1 RECOMMENDED CRITERIA 7711.2 RECOMMENDED TEST METHODS 81

SECTION 12 DIGITAL AUDIO CIRCUITS AND EQUIPMENT 8712.1 RECOMMENDED CRITERIA 8712.2 RECOMMENDED TEST METHODS 89

REFERENCE SECTION 93Ref. 1: Pulse and Bar test signals (ITU-R BT.451-2) 93Ref. 2: Staircase test signal (ITU-R BT.451-2) 94Ref. 3: Differentiating and shaping network 94Ref. 4: Typical K-rating graticule 95Ref. 5: 50 Hz Square-wave test signals (ITU-R BT.451-2) 96Ref. 6: Chrominance Pulse and Bar test signals 97Ref. 7: Characteristics of Weighting Filters for video noise measurements (ITU-R BT.567) 98Ref. 8: 100.0.100.0 Colour Bars (100%) 99Ref. 9: Characteristics of Filters for audio noise measurements (ITU-R BT.468-4) 100Ref. 10: Specification of Wow and Flutter meter (ITU-R BT.409-2) 101Ref. 10: Specification of Wow and Flutter meter (continued) 102Ref. 11: Specification of Rumble Meter to BS7063 103Ref. 12: Test Pattern for measurement of Telecine long-term Streaking 104Ref. 13: Test patterns for measurement of Telecine Flare 105Ref. 14: Measurement of Film frame steadiness 106Ref. 15: List of Test Films and Tapes for Telecine 106Ref. 16: Test Patterns for Camera Tests 107Ref. 16: Test Patterns for Camera Tests (continued) 108Ref. 16: Test Patterns for Camera Tests (continued) 109Ref. 16: Test Patterns for Camera Tests (continued) 110Ref. 16: Test Patterns for Camera Tests (continued) 111Ref. 17: Picture Zones 112Ref. 18: 5-point Impairment scale 113Ref. 19: Crosstalk and Phase Profiles 113Ref. 19: Crosstalk and Phase Profiles (continued) 114Ref. 19: Crosstalk and Phase Profiles (continued) 115Ref. 19: Crosstalk and Phase Profiles (continued) 116Ref. 19: Crosstalk and Phase Profiles (continued) 117Ref. 19: Crosstalk and Phase Profiles (continued) 118Ref. 20: Delay Inequality Test Signals 119Ref. 21: Non-linearity Test Sawtooth Signals 120


ITC Handbook of Technical Standards for Television Programme Production Issue 2.0 December 1996 V

Ref. 22: Non-linearity Test Staircase Signals 121Ref. 23: Typical Multiburst Test Signals 122Ref. 24: Colour Difference Noise Filter 123Ref. 25: Vertical Synchronising and Blanking waveformsError! Bookmark not defined. 124Ref. 26: Field interval Blanking of the Colour Burst 125Ref. 27: Allocation of VBI Lines 125Ref. 28: Insertion Test Signals 126Ref. 29: Teletext Data signals in the VBI 127Ref. 30: Widescreen signalling in Line 23 128Ref. 31: Status bits for Widescreen signalling 128Ref. 32: Ghost Cancellation Reference signals 129Ref. 33: Parameters for GCR signals 130Ref. 34: Analogue and Digital sync. And blanking timing 131Ref. 35: Timing reference signals 132Ref. 36: Audio channel status 133Ref. 37: Ramp signal for Noise Measurement 134Ref. 38: Colour Gamut in R, G, B and Y, Cr, Cb domains 134Ref. 39: Audio Timing Reference 135Ref. 40: Noise in the presence of signal 135Ref. 41: DFIM performance profile 136Ref. 42: IMD and Harmonic Distortion performance profile 136Ref. 43: Group Delay profile 137Ref. 44: 16:9 Telecine alignment test film 138

NOTES: 141


ITC Handbook of Technical Standards for Television Programme Production Issue 2.0 December 1996VI

INTRODUCTIONThis handbook contains performance figures for the main elements of the video and audio equipmentand the signal paths used in television programme production, and incorporates recommended testprocedures for checking compliance with these performance criteria. The main body of the ITCTechnical Performance Code requires licensees to use reasonable endeavours to ensure conformancewith these performance targets, stopping short of requiring conformance as an absolute condition.However, the ITC may at its discretion require conformance with specified targets if tests havedemonstrated poor performance resulting in a less than high standard of technical quality.

Developments in technology, for example resulting in the introduction of a new VTR format or newcamera technology, during the period of the licence might necessitate revision of this handbook. TheITC intends to discuss such revisions with licensees, as appropriate. Any revisions to existing Sections,or additional Sections, will be considered by the Technical Performance Working Party which consistsof a membership drawn from the ITC Engineering Division and the licensees.

Technical Performance Working Party MembershipC Girdwood - ITC (Chairman)

C Hunt - ITC (Secretary)

P Gray - Anglia Television

M Hughes - Carlton Television

R Hurley - Channel Four Television

R Soczywko - Granada Television

R White - Meridian Broadcasting

Past MembershipP Ballabon (London Weekend Television), I Dutton (Tyne Tees Television), C Hibbert (CarltonTelevision), C Hunter (Scottish Television), P Marshall (Channel Four Television), J Nichol (TyneTees Television), R Pickles (Granada Television), J Rogers (Yorkshire Television), T Ross (ScottishTelevision) and S Waring (Thames Television).

The Technical Performance Working Party would like to thank the many people and organisations fortheir help in the preparation of the Handbook.

Section 1: Video Circuits & Equipment within the signal path On-line version source EBU website

ITC Handbook of Technical Standards for Television Programme Production Issue 2.0 December 1996 1

SECTION 1VIDEO CIRCUITS AND EQUIPMENT WITHIN THE SIGNAL PATH

1.1 PERFORMANCE FIGURES (COMPOSITE PATHS)

1.1.1 Definitions and Operational Practices

Direct PathFor purposes of measurement the direct path is assumed to comprise the circuit from the agreedinterface with British Telecom or Transmission Operators equipment, through the Presentation andMaster Control switching and processing equipment back to the agreed interface with British Telecomor Transmission Operator's equipment.

The limits in brackets refer to the situation when a synchroniser is included in the path.

Worst PathFor the purposes of measurement, the worst path is assumed to comprise the following with allinterconnections carried out using the normal equipment routes:-

(i) The source studio mixer(ii) A looped VTR path(iii) A second studio mixer(iv) A second looped VTR path(v) The Presentation and Master Control PathThe tolerance limits do not include degradations due to signal sources such as cameras, telecines orvideo tape recorders, as tolerances for these are separately specified.

The limits in brackets refer to the situation when digital video effects are included in the path.

A measurement of the Worst Path parameters is normally only necessary after the completion of a newinstallation or a major re-installation.

Production PathFor the purposes of measurement the production path will comprise that part of the system that starts atthe output of originating equipment (camera or VTR) and that includes assignment switching, mixingand effects equipment and ends at the interface with a VTR or the Master Control Room. The pathmay be in a studio centre or outside broadcast scanner.

The limits in brackets refer to the situation when digital video effects are included in the path.

O.B. Link PathsOB link tolerances are related to an unspecified number of point-to-point SHF links. Measurement ismade at the final output of the link at which point connection to a permanent circuit would be made.

DirectPath

WorstPath

ProductionPath

O.B. LinkPath

1.1.2 Signal Levels(a) Signal Level

Adjustment Error0.7V2%

0.7V2%

0.7V2%

0.7V2%

(b) Signal Level Gain Stability 2% 5% 2% 2%


ITC Handbook of Technical Standards for Television Programme Production Issue 2.0 December 19962

DirectPath

WorstPath

ProductionPath

O.B. LinkPath

1.1.3 Linear Waveform Distortion(a) 2T Pulse-to-Bar Ratio % K

(1% K)1% K

(2% K)% K

(1% K)2% K

(b) 2T Pulse Response % K(1% K)

1% K(2% K)

% K(1% K)

2% K

(c) 2T Bar Response % K(1% K)

1% K(2% K)

% K(1% K)

2% K

(d) 50 Hz Square Wave Response % K(1% K)

1% K(2% K)

% K(1% K)

2% K

(e) Chrominance/Luminance GainInequality

3% 4% 3% 4%

(f) Chrominance/Luminance DelayInequality

20 ns 40 ns 20 ns 20 ns

1.1.4 Non-Linearity Distortion(a) Luminance Line Time Non-Linearity 3% 5% 3% 5%(b) Differential Phase 2 5 2 5(c) Burst/Chroma Phase 2 5 2 -(d) Differential Gain 3% 5% 3% 5%(e) Transient Gain Change, Luminance 5%(f) Transient Gain Change,

Chrominance5%

(g) Transient Gain Change, Sync 5%(h) Chrominance / Luminance Crosstalk - - - 3%1.1.5 Input/Output Impedance-Return Loss(a) Luminance -30 dB -30 dB -30 dB -30 dB(b) Chrominance -30 dB -30 dB -30 dB -30 dB(c) Low Frequency -30 dB -30 dB -30 dB -30 dB1.1.6 VLF Response(a) First Overshoot - - - 20%(b) Second Overshoot - - - 8%1.1.7 Noise(a) Weighted Luminance (RMS) -64 dB

(-60 dB)*-58 dB -64 dB

(-60 dB)*-55 dB

(b) Weighted Chrominance (RMS) -58 dB -52 dB -58 dB -52 dB(c) Total Low Frequency

Random and Periodic (p-p)-45 dB -45 dB -45 dB -40 dB

(d) Interchannel Crosstalk -55 dB -45 dB -52 dB -1.1.8 Modulation Derived Distortion

(Sound to Vision Crosstalk)



DirectPath

WorstPath

ProductionPath

O.B. LinkPath

(a) Sound Subcarrier Modulated - - - -52 dB(b) Sound Subcarrier Unmodulated

(Level of Intermodulation productsbetween sound andchrominance subcarriers)

- - - -57 dB

* The figure applies to 8-bit processors. If 9-bit processors are used the figure should beimproved by 3-4 dB.

1.2 RECOMMENDED TEST METHODS (COMPOSITE PATHS)

1.2.1 Test ConditionsBefore commencing a measurement, all test equipment should be checked for accuracy. Anyinaccuracies should be corrected if possible, or noted and allowed for in the measurement.

This section gives examples of test methods that use basic techniques. These examples do not precludethe use of other valid methods. The use of ITS type test signals is also not precluded but the ITUwaveforms referred to in these notes are regarded as the primary standard.

The signals specified below are applied to the path under test; when vision mixers are included in thepath then the route should include the shortest normally used path through each vision mixer and anyprocessing amplifiers that are normally used. The processing amplifiers should be set to the mode inwhich they are normally used operationally.

1.2.2 Signal Levels

(a) Signal Level Adjustment ErrorThe test may be carried out using a calibrated television waveform monitor.

The signal level adjustment error may be measured by using a 75 ohm generator of the 2T Pulse andBar test signal as shown in Reference Section, Ref. 1. The generator should be adjusted so that the baramplitude is 700 mV and the synchronising pulse amplitude is 300 mV. The sine-squared pulse isignored in this application. The difference in amplitude of the bar centre at the output, expressed as apercentage of 700 mV, is taken as the signal level adjustment error.

(b) Signal Level Gain StabilityHaving completed the measurements in 1.2.2 (a), no level adjustments should be made for a period ofone hour. The measurements of 1.2.2 (a) should then be repeated using the identical path and anychange recorded as the parameter for this section.

1.2.3 Linear Waveform Distortion

(a) 2T Pulse-to-Bar RatioThe test signal should be the 2T Pulse and Bar Waveform as specified in Reference Section Ref. 1.

The pulse-to-bar K-rating is defined as:

%1004

xP

PBK =

Where B and P are the amplitudes of the bar and pulse respectively.

Therefore, in practice, to make the measurement, the pulse will be taken as reference.



Set the pulse amplitude to be 100% on the centre scale of an appropriate graticule (Reference SectionRef. 4) and divide by four the percentage difference in amplitude between the pulse and the barmeasured at its mid-point, to obtain the K-rating.

When the waveform is subject to line tilt or an extended distortion along the leading edge at the top ofthe bar, the amplitude of the bar must be measured at its midpoint after first setting the blanking levelmid-way between two successive bars to 0%.

b) 2T Pulse ResponseThe test signal should be the 2T Pulse and Bar Waveform as specified in Reference Section, Ref. 1.Measurement may be made using a graticule such as that shown in Reference Section, Ref. 4.

The vertical gain is adjusted to make the pulse amplitude 100% and then the vertical shift moved tobring the blanking level onto the base line at 30%. The horizontal gain is advanced and the horizontalshift adjusted to make the waveform touch the H.A.D. markers on the 80% line. With normal gain thegraticule markers are 2% K and 4% K. For 1% K and 2% K the calibrated vertical gain is advanced by2. For limits of % K and 1% K the pulse amplitude is first set to 80% and the calibrated verticalgain then advanced by 5.

If it is desired to measure the K rating exactly, the variable vertical gains should be adjusted until theworst pulse overshoot just touches the inner limits. The calibrated gain is then returned to normal andthe amplitude of the pulse measured (P%) then

%200gainCalibratedxP

K =

This is illustrated in the following table:-

Pulse Amplitude 5 Gain100 0.4% K80 0.5% K67 0.6% K

57.5 0.7% K50 0.8% K

(c) 2T Bar ResponseThe test signal should be the 2T Pulse and Bar waveform as specified in Reference Section, Ref. 1.

The horizontal timebase of the oscilloscope is adjusted so that the half amplitude points of the barreach the outer limits marked on a graticule such as that shown in Reference Section, Ref. 4.

Ignoring the first and last 2.5% (0.625 ms) of the bar, the deviation from its mid-point, expressed as apercentage of its amplitude at that point, is the K rating of the bar. It must be emphasised thatmeasurements are made using only half the bar, the worst half being quoted as the result. It is wrong tomeasure the whole bar and divide by two to obtain the K rating.

(d) 50 Hz Square Wave ResponseThe test signal should be the 50 Hz square wave test signal as specified in Reference Section, Ref. 5.

With the horizontal scan at field rate the 50 Hz signal is adjusted as in 1.2.3. (c). For a stationarydisplay the signal must contain field synchronising pulses. Again, ignoring the first and last 2.5%(250 ms) the percentage deviation of the worst half divided by 2 is the K rating of the bar. (It may benoted that for the same deviation on the display a 4% K figure for the bar response looks the same as a2% K for 50 Hz).



(e) Chrominance/Luminance Gain InequalityThe measurement is best made using the 2Tc non-composite waveform (Reference Section, Ref. 6b).The 50% luminance pedestal is used to calibrate the vertical gain of the oscilloscope. The chrominanceamplitude is then measured directly.

NOTE: The use of the composite 2Tc waveform with a gain and delay test set will produce anerroneous result in the presence of chrominance/luminance crosstalk.

(f) Chrominance/Luminance Delay InequalityThe measurement is made using a 2Tc composite Pulse-and-Bar signal (Reference Section, Ref. 6a)and a delay measuring test set where available.

The output of the test set is viewed on an oscilloscope and the test set adjusted to cancel any pathchrominance/luminance delay inequality. If a test set is not available then the level of distortion should beestimated by examining the sinusoidal distortions at the bottom of the 2Tc composite pulse on awaveform monitor or oscilloscope. The method is described in Part B, Guidelines.

1.2.4 Non-Linearity Distortion

(a) Luminance Line Time Non-LinearityThe test signal consists of a 5-step staircase (Reference Section, Ref. 2 occupying one line in everyfour, followed by three lines of black or white. Measurements are made with three lines of white (baron) and with three lines of black (bar off) and the worst result quoted.

It should be noted that the staircase with added sub-carrier waveform is used to conform with C.C.I.R.recommended practice.

At the receiving end the test signal is passed through a suitable differentiating network (ReferenceSection, Ref. 3) and amplifier and displayed on an oscilloscope. The result is a train of five pulses.Non-linearity is measured as the difference in amplitude between the largest and the smallestexpressed as a percentage of the largest.

i.e. %100max

minmax xE

EE

(b) Differential PhaseThe test signal should be a 5 step staircase with added subcarrier (Reference Section, Ref. 2).

The differential phase may be measured by using a vectorscope in the line-time mode. The six sectionsof subcarrier are compared for their phase relationships taking the blanking level section as areference. The differential phase is defined as the largest departure in phase from that reference.Measurements are made with the white bar on and with the white bar off and the worst measurement isquoted.

(c) Burst/Chroma PhaseBurst/Chroma Phase errors may be measured as follows. Display the output of a colour bar generatordirectly on a vectorscope and after aligning the burst on the graticule, carefully measure the phasedisplacement (if any) of the BLUE bar. Apply the colour bar signal to the equipment or path under testand display the output signal on the vectorscope. After aligning the burst on its graticule, measureagain the BLUE bar phase displacement. Phase measurement minus the phase displacement of theoriginal signal indicates the burst/chroma distortion due to the equipment or path under test.

(d) Differential GainThe test signal should be a 5 step staircase with added subcarrier (Reference Section, Ref. 2.)



The differential gain may be measured by using a vectorscope in the line time mode. The six sectionsof subcarrier are compared for their amplitude relationship and taking the blanking level section as areference, the differential gain is defined as the largest departure in amplitude from that reference.Measurements are made with the white bar on and with the white bar off and the worst measurement isquoted.

NOTE ON TRANSIENT DISTORTION APPLICABLE TO SUB-SECTIONS (e), (f) & (g)BELOWThe transient gain change due to a change of APL is defined as the maximum transient departure in theamplitude of each component from that which existed before the change in APL, expressed as apercentage of the original amplitude. Separate measurements are made on the five step staircase withadded subcarrier (Reference Section, Ref. 2), with the APL changed from low (intervening lines atblanking level) to high (intervening lines at white level) and from high to low.

(e) Transient Gain Change, Luminance (see note above)At the receiving end the test signal is passed through a suitable differentiating network (ReferenceSection, Ref. 2), amplified and displayed on an oscilloscope (some commercial filters with amplifiersoverload at normal signal level and require some 10 dB reduction of input signal level).

The oscilloscope should be synchronised by an external source and the black level clamp or dc restorershould be switched off. Movement of the base line of the waveform when the APL is changedindicates overload or some other non-standard measuring condition.

Set up the oscilloscope to make the amplitude of each of the spikes corresponding to the steps in turnequal to 100% with intervening lines at black. Measure the maximum transient departure from 100%of each of the spike amplitudes when the APL is switched from low to high and vice-versa.

The largest departure from 100% is taken as the result and it should be noted whether the change ispredominantly on only one spike and if so, on which spike.

(f) Transient Gain Change, Chrominance (See note above)Set up the oscilloscope using the chrominance filter and measure the maximum transient departurefrom 100% of the peak-to-peak subcarrier amplitude on the third step, when the APL is switched fromlow to high and vice-versa.

(g) Transient Gain Change, Sync (See note above)Using the differentiating network, amplifier and oscilloscope as in (e) above, set the oscilloscope sothat the amplitude of the positive spike corresponding to the trailing edge of sync equals 100% withintervening lines at black.

Measure the maximum transient departure from 100% of the spike amplitude when the APL isswitched from low to high and vice-versa.

(h) Chrominance to Luminance CrosstalkThe 2Tc pulse and bar waveform (Reference Section, Ref. 6b) should be used for the test. Thecrosstalk, which manifests itself as a change in the mean level of the pedestal during transmission ofthe chrominance component, should be expressed as a percentage of the picture level, as determinedby the measurement described in Para 1.2.2. (a), (nominally 700 mV).

1.2.5 Input/Output Impedance - Return Loss

(a)(b)(c) Return LossThe measuring point for this test is the same interface as defined in Section 1.1.1. Direct Path.



The test is first carried out using a 2T pulse-and-bar waveform in conjunction with a return loss bridgewhich should first be calibrated using two very closely matched, 75 0.1% ohm resistors.

In addition, the same leads should be used for calibration and measurement and the reference path leadshould be identical to the main path connection. With one return loss bridge presently available, acalibration distortion of -40 dB is provided; if this bridge is used the output is displayed on anoscilloscope and adjusted to give a reference display (5 divisions for example). The bridge is thenrearranged to include the circuit under test and the unbalance output measured. The return loss is thencalculated by linear interpolation. For large mismatches a 10 dB switch is incorporated in the bridge toallow calibration at -30 dB. When measuring output impedance the input signal should be removedand the input terminated. For very small return loss measurements an external trigger to theoscilloscope is often necessary.

The test should be repeated using the 2Tc pulse-and-bar and the 50 Hz waveforms. These results arerespectively recorded as the (a) Luminance, (b) Chrominance and (c) Low Frequency parameters.

1.2.6 V.L.F. ResponseThe signal used should switch all lines to black and white. The switching should occur at a sufficientlyslow rate to allow the waveform to settle before the following transition. The 1st and 2nd overshoots ofblanking level variation are measured (Fig. 1.1) and expressed as a percentage of standard picture level(700 mV peak-to-peak).

It should be noted that the dc change ("c" in Fig. 1.1) is not measured since it is a function only of thetest signal.

Both the black to white and the white to black transitions are measured and the worst result quoted.

A dc-coupled oscilloscope with a very slow timebase may be used for these measurements.Alternatively, if only a television waveform monitor is available, a line rate display should be usedwith the Y amplifier switched to dc coupled and the dc restorer switched off.

Fig. 1.1

1.2.7 NoiseMeasurement is made using a 10% lift signal. Care should be taken that the noise of the generatedsignal is not significant. When measurements are made on paths containing digital processingequipment the 10% lift signal may be adjusted slightly to minimise the effects of quantisation noise ora ramp waveform may be used.

(a) Weighted LuminanceMeasurement is made in the band 10 kHz (7.5 kHz) - 5.0 MHz using RMS detection. Thecharacteristic of the luminance weighting filter is shown in Reference Section, Ref. 7.



(b) Weighted ChrominanceMeasurement is made in the band 3.5 MHz - 5.5 MHz as defined only by the characteristic of theweighting filter as shown in Reference Section, Ref. 7 and using RMS detection.

(c) Total L.F. Random and PeriodicMeasurement is made peak-to-peak in the band 40 Hz - 10 kHz (7.5 kHz).

(d) Interchannel CrosstalkOne channel is selected as the one to be measured as the receiver of crosstalk interference. Thischannel is fed with a blanking and sync waveform.

Another channel that is considered to be the nearest electrically adjacent channel is used as the hostilechannel. This is fed with Colour Bars (Reference Section, Ref. 8).

The signal-to-crosstalk ratio is defined as the ratio, expressed in decibels, of the normal peak-to-peakamplitude of the picture signal to the peak-to-peak amplitude of the crosstalk waveform.

1.2.8 Modulation Derived Distortion (Sound to Vision Crosstalk)

a) Sound Subcarrier ModulatedMeasured with whole-time 5-step staircase, without chrominance sub-carrier, into the vision channeland +8 dBu at 1 kHz into the sound channel. The crosstalk should be measured unweighted, peak-to-peak, in the frequency band 40 Hz to 10 kHz (7.5 kHz) using a noise measuring set. The result isexpressed with reference to standard picture level (700 mV p-p).

(b) Sound Subcarrier UnmodulatedMeasured with whole time 5-step staircase, with chrominance subcarrier, into the vision channel andno sound modulation. The crosstalk should be measured luminance weighted, peak-to-peak in thefrequency band 40 Hz to 5.0 MHz, using a noise measuring set. The result is expressed with referenceto standard picture level (700 mV p-p).

N.B. Other methods of measurement using spectrum analysis are acceptable.

1.3 PERFORMANCE FIGURES (COMPONENT PATHS)This section gives the performance figures for production component paths (excluding digital effectsequipment).

A Company may reserve the right to test all three component channels to the luminance channelperformance. This may be necessary in ensuring good chroma-keying signals where a wide bandwidthin the colour difference channels is required. In this case the linear waveform distortions should bemeasured using the 2T Pulse and Bar signal and the noise performance should be the same as in theluminance channel.

1.3.2 Signal Levels

(a) Signal LevelAdjustment Error

0.7 V 2%

(b) Signal Level Gain Stability 2%1.3.3 Linear Waveform Distortions (2T Pulse and Bar in Luminance

and 5T Pulse and Bar in Colour Difference Channels)(a) Pulse-to-Bar Ratio 0.5% K(b) Pulse Response 0.5% K



(c) Bar Response 0.5% K(d) 50 Hz Square Wave Response 0.5% K1.3.4 Delay Inequality between all Component Channels

Timing difference 10 ns1.3.5 Non-Linear Waveform Distortion(a) Amplitude Non-Linearity 3%(b) Component Crosstalk -50 dB1.3.6 Noise(a) Weighted Luminance (RMS) -64 dB (-60 dB)*(b) Colour Difference (RMS) - 1.6 MHz low pass filter -64 dB(c) Total Low Frequency in Luminance Channel (p-p) -45 dB(d) Total Low Frequency in Colour Diff. channels (p-p) -43 dB* The figure applies to 8-bit processors. If 9-bit processors are used the figure

should be improved by 3-4 dB.

1.4 RECOMMENDED TEST METHODS (COMPONENT PATHS)

1.4.1 Test ConditionsThe analogue component signals (Y, Pr and Pb) will be related to the colour separation signals (R, Gand B) by the following matrix equations:

Y 0.299 0.587 0.114 RPb = -0.169 -0.331 0.500 . GPr 0.500 -0.419 -0.081 B

The colour separation signals have normal peak amplitudes of 700 mV. Synchronising signals may beadded to or kept separate from the luminance component.

The following methods are relevant when component paths are being measured and it may beconvenient to use a waveform monitor capable of displaying the three components simultaneously:

1.4.2 Signal Levels

(a) Signal Level Adjustment ErrorThe test may be carried out using a calibrated television waveform monitor and suitable graticule.

The insertion gain may be measured by using a 75 ohm generator of the 2T and 5T Pulse and Bar testsignals as shown in the Reference Section, Ref. 1. The 2T signal is fed to the Luminance Channel andthe 5T to the Colour Difference channels when required. The generator should be adjusted so that thebar amplitude is 700 mV in both cases and the synchronising pulse amplitude is 300 mV in theluminance channel. The difference in amplitude of the bar centre at the output, expressed as apercentage of 700 mV, is taken as the signal level adjustment error.

(b) Signal Level Gain StabilityHaving completed the measurements in 1.3.2 (a), no level adjustments should be made for a period ofone hour. The measurements should be repeated using the same channels and any change recorded asthe parameter for this section.



1.4.3 Linear Waveform DistortionsLinear waveform distortions (a) to (c) are measured using the 2T Pulse and Bar test signal in the Y(luminance) channel and the 5T Pulse and Bar test signal in the Pr and Pb (colour difference) channels.The waveforms are shown in the Reference Section, Ref. 1.

(a) Pulse-to-Bar RatioThe pulse-to-bar K rating is defined as:

%1004

xP

PBK =

where B and P are the amplitudes of the bar and pulse respectively.

In practice, the pulse will be taken as the reference during measurement.

Set the pulse amplitude to be 100% on the centre scale of an appropriate graticule (Reference Section,Ref. 4) and divide by four the percentage difference in amplitude between the pulse and the barmeasured at its mid-point, to obtain the K rating.

When the waveform is subject to line tilt or an extended distortion along the leading edge at the top ofthe bar, the amplitude of the bar must be measured at its mid-point after first setting the reference level(blanking for Y) mid-way between two successive bars to 0%.

(b) Pulse ResponseMeasurement may be made using a graticule such as that shown in the Reference Section, Ref. 4.

The vertical gain is adjusted to make the pulse amplitude 100% and then the vertical shift moved tobring the reference level (blanking for Y) onto the baseline at 30%. The horizontal gain is advancedand the horizontal shift adjusted to make the waveform touch the H.A.D. markers on the 80% line.With normal gain the graticule markers are 2% K and 4% K. For 1% K and 2% K the calibratedvertical gain is increased by x2. For 0.5% K and 1% K the pulse amplitude is first set to 80% and thecalibrated vertical gain is increased to x5.

If it is desired to measure the K rating exactly, the variable vertical gains should be adjusted until theworst pulse overshoot just touches the inner limits. The calibration gain is then returned to normal andthe amplitude of the pulse measured (P%) then

%200GainCalibratedxP

K =

This is illustrated in the following table:


57.5 0.7% K50 0.8% K

(c) Bar ResponseThe horizontal timebase of the waveform monitor or oscilloscope is adjusted so that the half amplitudepoints of the bar reach the outer limits marked on a graticule such as that shown in the ReferenceSection, Ref. 4.

Ignoring the first and last 2.5% (0.625ms) of the bar, the deviation from its mid-point, expressed as apercentage of its amplitude at that point, is the K rating of the bar. It must be emphasised that



measurements are made using only half the bar, the worst half being quoted as the result. It is wrong tomeasure the whole bar and divide by two to obtain the K rating.

(d) 50 Hz Square Wave ResponseThe test signals are the 50 Hz square waves shown in the Reference Section, Ref. 5. The 0V to700 mV signal is used in the Y channel and the -350 mV to +350 mV signal is used in the Pr and Pbchannels.

With the horizontal scan at field rate the 50 Hz signal is adjusted to coincide with the appropriate barmarkings on the graticule. For a stationary display the signal must contain field synchronising pulses(Y) or the waveform monitor must be externally triggered from the same synchronising pulses (Pr andPb). Ignoring the first and last 2.5% (250 ms) of the bar, the percentage deviation of the worst halfdivided by two is the K rating of the bar. (It may be noted that for the same deviation on the display a4% K figure for the bar response looks the same as a 2% K figure for 50 Hz).

1.4.4 Delay InequalityThe test signal consists of sinusoids as shown in the Reference Section, Ref. 20 where the frequency ofthe sinusoid applied to the luminance channel is 500 kHz and that to the colour difference channels is502 kHz. When these signals are subtracted a null appears half way along active line time giving theappearance of a "bowtie". A timing difference in the paths gives rise to a positional displacement ofthe null by 1ms for about 4ns of timing error. Markers on some of the picture lines enable a directreading of any timing errors to be made. The method is not well suited for showing timing differenceswhich are not constant throughout the line time.

In this situation, or when there is noise or the sinewaves are distorted, a dual channel oscilloscope withdelayed timebase and writing speed in the order of 20 ns per division should compare the coincidenceof rising or falling slopes of the sinewaves shown in the Reference Section, Ref . 20.

The delaying timebase should be triggered from the rising edge of the luminance pedestal so that Prand Pb can be compared with Y. High gain should be used in the vertical amplifiers to give a steepslope to the edges being measured and the oscilloscope delay time multiplier control used to inspectthe full line period. The worst error should be quoted.

The tracking of the oscilloscope input amplifier controls can be checked using the staircase at the startof the waveform, the step amplitudes being designed to match the 5, 10 and 20 mV per divisionsequence of many general purpose instruments.

When this method is used, it is also beneficial if some lines of the test signals are left unmodulated togive a line through the sinewave crossings, aiding the vertical positioning of the traces at highmagnifications.

If a high speed oscilloscope is not available, an estimate can be made using matched and calibratedswitchable delays in both oscilloscope inputs (to account for insertion delay) and adjusted for a visualtiming null. Again this should be checked across the line period.

1.4.5 Non-Linear Waveform Distortion

(a) Amplitude Non-LinearityThe waveforms used are ramp signals shown as typical examples in the Reference Section, Ref. 21. Inorder that the system may be tested under a wide range of APL, the signal should consist of 6 lines oframp in every 24, with the intervening lines at black or white. Measurements are made with 18 lines ofwhite (bar on) and then 18 lines of black (bar off) and the worst result quoted.

To make the measurement, the output of the appropriate component channel is differentiated by asuitable network as in the Reference Section, Ref. 3 and the mid-point of the resultant signal level



made to occupy 100% on an oscilloscope. The error is then the peak-to-peak percentage deviation overthe duration of the differentiated ramp.

If the significant noise is present, making the assessment of non-linearity difficult and the rampwaveforms have been inspected to ensure that there are no quantisation errors, then staircasewaveforms similar to those shown in the Reference Section, Ref. 22 may be used. The signal shouldconsist of 6 lines of staircase in every 24 with the intervening lines at black and white. Measurementsare made with 18 lines of white (bar on) and then with 18 lines of black (bar off) and the worst resultquoted.

At the receiving end the test signal is passed through the differentiating network and displayed on anoscilloscope to show a train of five pulses. Non-linearity is given by the difference in amplitude betweenthe largest and smallest pulse expressed as a percentage of the largest.

i.e. %100max

minmax xE

EE

(b) Component CrosstalkTwo of the component channels are energised with the multiburst test signals shown in the ReferenceSection, Ref. 23 and the crosstalk into the "dormant" third component is measured peak-to-peak. Theresult is expressed in dB relative to 700 mV

NOTE: Some waveform monitors may have insufficient gain to achieve 100% amplitude when aline rate ramp such as that shown in Reference 21 is differentiated. In cases such as these,the ramp signals provided as `valid' waveforms from Component Test Signal Generatorsmay be used, as the shorter duration of these ramps give a larger amplitude pedestal whendifferentiated. Alternatively, the line rate signal may be used as for the case when noise ispresent.

1.4.6 NoiseMeasurement is made using a 10% lift signal. Care should be taken that the noise of the generatedsignal is not significant. When measurements are made on paths containing digital processingequipment the 10% lift signal may be adjusted slightly to minimise the effects of quantisation noise.

(a) Weighted LuminanceMeasurement is made on the Y channel in the band 10 kHz (7.5 kHz) - 5.0 MHz using RMSdetection. The characteristic of the luminance weighting filter is shown in the Reference Section,Ref. 7.

(b) Colour Difference NoiseMeasurement is made on the Pr and Pb channels in the band 10 kHz -1.6 MHz using RMS detection.The Colour Difference filter having the characteristic shown in the Reference Section, Ref. 24 shouldbe used. Note that this network has a 6 dB insertion loss and therefore the measured figure should becorrected accordingly.

(c) Total Low Frequency Noise in Luminance ChannelMeasurement is made unweighted in the band 40 Hz - 10 kHz (7.5 kHz) using peak-to-peak detection.

(d) Total Low Frequency Noise in Colour Difference ChannelsMeasured the same as in the Luminance Channel.

Section 2: Audio Circuits & Equipment in the Signal Path On-line version source EBU website


SECTION 2AUDIO CIRCUITS AND EQUIPMENT WITHIN THE SIGNAL PATH

2.1. PERFORMANCE FIGURES

2.1.1 Definitions and Operational Practices

Direct PathFor purposes of measurement the direct path is assumed to comprise the circuit from the agreedinterface with British Telecom or Transmission Operator's equipment, through the Presentation andMaster Control switching and processing equipment back to the agreed interface with British Telecomor Transmission Operator's equipment.

Worst PathFor the purposes of measurement, the worst path is assumed to comprise the following, with allinterconnections carried out using the normal equipment routes:-(i) A studio mixer

(ii) A looped VTR path

(iii) A second studio mixer

(iv) A second looped VTR path

(v) The presentation and Master Control Path.

The input signal may either be an assigned source or commence at a studio wall box at a microphoneinput.

The tolerance limits do not include degradations due to signal sources such as tape recorders, astolerances for these are separately specified.

A measurement of the Worst Path parameters is normally only necessary after the completion of a newinstallation or a major re-installation.

Production PathFor the purposes of measurement the production path will comprise that part of the system that starts atthe output of originating equipment (microphone, disc reproducer, ATR or VTR etc). and that includesassignment switching and mixing and ends at the interface with recording equipment or the MasterControl Room. The path may be in a studio centre or outside broadcast scanner.

O.B. Link PathsO.B. Link tolerances are related to an unspecified number of point-to-point SHF links. Measurement ismade at the final output of the link at which point connection to a permanent circuit would be made.



DirectPath

WorstPath

ProductionPath

O.B. LinkPath

2.1.2 Output Signal Level(a) Output signal level at agreed

interface after line-up0 dBm

0.25 dB0 dBm

0.5 dB0 dBm

0.25 dB0 dBm

0.25 dB(b) Gain Stability, variation of

insertion gain during one hour0.25 dB 0.5 dB 0.25 dB 0.25 dB

2.1.3 Amplitude/Frequency Response(a) 40 Hz-15 kHz +1 dB +1 dB +1 dB +0.5 dB

w.r.t.1 kHz -2 dB -3 dB -2 dB -3.0 dB(b) 125 Hz-10 kHz +1 dB +1 dB +1 dB +0.5 dB

w.r.t.1 kHz -1 dB -2 dB -1 dB -2.0 dB2.1.4 Total Harmonic Distortion(a) 1 kHz at -10 dBu 0.5% 0.5% 0.5% 1.0%(b) 1 kHz at +8 dBu 0.5% 1.0% 0.5% 1.0%(c) 80 Hz at -10 dBu 0.5% 0.5% 0.5% 1.0%(d) 80 Hz at +8 dBu 0.5% 2.0% 1.0% 1.0%(e) Input Overload - - 17 dB -2.1.5 Signal/Noise Ratio(a) 0 dBu input(i) Weighted, Random Peak 60 dB 56 dB 60 dB 42 dB(ii) Unweighted, Random Peak - - 63 dB 47 dB(b) -50 dBu input(i) Weighted,Random Peak - 53 dB 56 dB -(ii) Unweighted,Random Peak - - 60 dB -(c) Interchannel Crosstalk,

Weighted, Peak53 dB 53 dB 53 dB -

2.1.6 Modulation Derived Distortion(a) Vision to Sound Crosstalk,

Weighted- - - 45 dB

DUAL CHANNEL SOUND PATHS ONLY2.1.7 Level Difference Between A and B Channels(a) 40 Hz-15 kHz 1.0 dB 1.5 dB 1.0 dB 1.0 dB(b) 125 Hz-10 kHz 0.5 dB 1.0 dB 0.5 dB 0.5 dB2.1.8 Crosstalk Between A and B Channels(a) 40 Hz -35 dB -26 dB -35 dB -35 dB(b) 40 Hz-315 Hz -6 dB/

octave-6 dB/octave

-6 dB/octave

-6 dB/octave

(c) 315 Hz-6.3 kHz -53 dB -44 dB -53 dB -53 dB(d) 6.3 kHz-15 kHz +6 dB/

octave+6 dB/octave

+6 dB/octave

+6 dB/octave

(e) 15 kHz -45 dB -36 dB -45 dB -45 dB



DirectPath

WorstPath

ProductionPath

O.B. LinkPath

Profiles are shown in Reference Section, Ref. 19 (a) and Ref. 19 (b)2.1.9 Phase Difference Between A and B Channels(a) 40 Hz 20 30 20 20(b) 40 Hz-200 Hz Oblique

SegmentObliqueSegment

ObliqueSegment

ObliqueSegment

(c) 200 Hz-4 kHz 10 15 10 10(d) 4 kHz-15 kHz Oblique

SegmentObliqueSegment

ObliqueSegment

ObliqueSegment

(e) 15 kHz 20 30 20 20Profiles are shown in Reference Section, Ref. 19(f) and Ref. 19 (g)

2.2 RECOMMENDED TEST METHODS

2.2.1 Test ConditionsNormally signal levels are measured as voltages irrespective of impedance and are quoted in decibelswith reference to O dBu, where O dBu corresponds to 0.775 volts, RMS. This definition of signal levelapplies throughout this Han dBook of Technical Standards for equipment measurements but does notapply to line measurements or where it is separately defined.

2.2.2 Output Signal LevelThe measurements may be made at any overall gain setting. The PPMs, which are used to control theprogramme output levels of each mixer, will be used as the indicating meters.

With the input level set constant at -50 dBu for microphone level inputs, or O dBu for line level inputs,the greatest change occurring in one hour in the output is defined as the gain stability.

2.2.3 Amplitude/Frequency ResponseThis measurement may be made at any gain setting up to the maximum available; the output levelshould be O dBu approximately on each output when the measurement is made.

Tests should be made at the following frequencies and the measurements should be referenced to thelevel at 1 kHz.

40 Hz, 60 Hz, 125 Hz, 250 Hz, 500 Hz,

1 kHz, 2 kHz, 4 kHz, 6 kHz, 8 kHz,

10 kHz, 12 kHz, 15 kHz,Additional tests should be made to ensure that the overall response falls off smoothly outside thisfrequency band.

It should be noted that, as this test is a measurement of the variation of gain of the equipment withfrequency, corrections should be made for any variations in the input level with frequency.

2.2.4 Total Harmonic Distortion(i) For microphone channels, -50 dBu input with normal balance attenuator, channel, group and

main fader settings to achieve O dBu output.

(ii) For line level channels, O dBu input with normal balance attenuator, channel, group and mainfader settings to achieve O dBu output.



The input signal level is varied to give an output level of first -10 dBu and then +8 dBu w.r.t. line-up.At each level tests are made at 80 Hz and 1 kHz.

For microphone inputs only, additional tests of input overload capability at 80 Hz and 1 kHz are made.The input signal level is slowly increased and the channel fader adjusted to keep the output level at+8 dBu (ie peak signal level) until the onset of evident distortion (for the purposes of this measurementthis is defined at 3%). The increase in input signal level above normal peak input level, -42 dBu, is theinput overload capability.

2.2.5 Signal/Noise RatioThe noise levels are measured using a test set incorporating a standard PPM (to BS 6840), and a lownoise amplifier with calibrated variable gain. The 'unweighted' bandwidth is constrained in accordancewith ITU-R BT.468-4, shown in Reference Section, Ref. 9(a) and the 'weighted' frequency response isdetermined by the ITU network as defined in ITU-R BT.468-4 shown in Reference Section, Ref. 9(b).

1 kHz tone at the appropriate level is fed to the path under test and the gain of the test set is adjusted sothat the PPM gives a scale reading of '4' (i.e. O dBu). The input signal is then replaced by a termination(as defined below) and the gain of the test set is re-adjusted so that the PPM again peaks to the scalereading of '4'. The signal/noise ratio is the difference between settings of test set gain. Themeasurements are made both weighted and unweighted.

(a) Line Level Path (O dBu)The input should be terminated in 600ohms.

(b) Microphone Input (-50 dBu)Balance attenuator, channel, group and main faders should be set as for normal operation. The inputshould be terminated in 200 ohms directly at the injection point.

(c) CrosstalkThe interfering signal, consisting of a 7 kHz tone, is fed to an adjacent input of each sound desk andswitching matrix in the path under test. The interfering path is lined up, using separate group andoutput faders where this is possible without mixing with the path under test. Desk inputs may be atmicrophone level (-50 dBu) or line level (O dBu). When the interfering path has been lined up theinput level is raised by 8 dB. The input of the path under test is terminated and the peak, weightedoutput level of the path under test is then measured on a noise meter. A bandpass filter may be neededto separate the crosstalking tone from random noise.

2.2.6 Modulation Derived Distortion (Vision to Sound Crosstalk)Measured as noise (Para 2.2.5), with vision channel modulated by 100% amplitude, 100% saturatedcolour bars.

DUAL CHANNEL SOUND PATHS ONLY

2.2.7 Level Difference Between A and B ChannelsFor any signal path one of four possible input conditions will be applicable.

(i) Microphone inputs to stereophonic channel - stereophonic circuits throughout.(ii) Microphone input to monophonic channel - stereophonic signals derived in a 'pan-pot'.(iii) Line inputs to stereophonic channel - stereophonic circuits throughout.(iv) Line input to monophonic channel - stereophonic signals derived in a 'pan-pot'.



With stereophonic input channels, test signals (initially at 1 kHz) from a common source should beinjected into both channel inputs, the channels being lined up in the normal way. The output levelsfrom the A and B chains should be measured at frequencies between 40 Hz and 15 kHz and thedifferences calculated.

2.2.8 Crosstalk Between A and B ChannelsA test signal at 1 kHz from a common source should be injected into both channel inputs, the channelsbeing lined up in the normal way.

In the case of stereophonic channels, the test signal should then be injected into the input of the Achannel, the input of the B channel being terminated in 200 ohms for microphone inputs and 600 ohmsfor line inputs. The levels of the signals on the A and B outputs should be measured and the difference(i.e. crosstalk) calculated. The inputs should then be reversed and the measurements taken again toascertain the crosstalk under this configuration.

In the case of monophonic input channels test signals should be injected and the channel routing selectorswitched so that the signal is fed to only one output. The levels of the wanted signal on this output and theunwanted signal on the other should be measured and the difference (i.e. crosstalk) calculated. Thechannel routing selector should then be switched so that the input is fed to the other output and themeasurements taken again to ascertain the crosstalk under this configuration.

Measurements should be made at frequencies between 40 Hz and 15 kHz. Profiles for Crosstalkperformance are shown in Reference Section, Ref. 19 (a) and Ref. 19 (b)

2.2.9 Phase Difference Between A and B ChannelsFor any signal path, one of the four input conditions described in Section 3.2.7 above will beapplicable.

With stereophonic input channels, test signals (initially at 1 kHz) from a common source should beinjected into both channel inputs, the channels being lined up in the normal way. The phase differencebetween the outputs of the A and B chains should be measured and the tests repeated at frequenciesbetween 40 Hz and 15 kHz.

In the case of monophonic input channels, a test signal (initially at 1 kHz) should be injected into thechannel input, the channel being lined up in the normal way. The test may be made with the 'pan-pot'set in any position. The phase difference between the outputs of the A and B chains should bemeasured and the tests repeated at frequencies between 40 Hz and 15 kHz. Profiles for Phaseperformance are shown in Reference Section, Ref. 19 (f) and Ref. 19 (g).



[THIS PAGE INTENTIONALLY BLANK]

Section 3: Video Tape Recorders On-line version source EBU website


SECTION 3VIDEO TAPE RECORDERS

3.1. PERFORMANCE FIGURES (COMPOSITE RECORDERS)

3.1.1 Definitions and Operational PracticesTolerances listed for video tape recorders refer to a single recording and replay not necessarily on thesame machine.

The tolerances are based on full field measurements and the most common and straightforwardmethods of measurement are given in 3.2. Where alternative methods, giving more accurate results, areavailable these are mentioned in the appropriate paragraph.

The tolerances given below apply to both quadruplex and helical recorders, which lay down PALtracks. They may also apply to component recorders if these are tested in the PAL domain usingsuitable codec pairs.NOTE: The use of VTRs not fully meeting this specification should be the subject of discussion

with the ITC where the subjective quality of the recordings justifies this.

VIDEO TOLERANCES3.1.2 Output Signal Level(a) Adjustment Error 2.0%(b) Gain Stability (over 1 hour) 2.0%3.1.3 Linear Waveform Distortion(a) 2T Pulse-to-Bar Ratio 1.5% K(b) 2T Pulse Response 1.5% K(c) 2T Bar Response 1.5% K(d) 50 Hz Square Wave Response 1.5% K(e) Chrominance/Luminance Gain Inequality 3%(f) Chrominance/Luminance Delay Inequality 20 ns3.1.4 Non-Linearity Distortion(a) Luminance Line Time Non-Linearity 4%(b) Differential Phase 5(c) Differential Gain 5%3.1.5 Noise(a) Weighted Luminance (RMS) -52 dB(b) Weighted Chrominance (RMS) -46 dB(c) Total Low Frequency Random and Periodic (p-p) -46 dB(d) Moire and Chrominance Modulation Noise -25 dB

AUDIO TOLERANCES3.1.6 Output Signal Level(a) Signal level at output after line-up 1.0 dB(b) Gain Stability 0.5 dB



3.1.7 Amplitude/Frequency Response(a) 40 Hz - 15 kHz w.r.t 1 kHz 2.0 dB(b) 125 Hz - 10 kHz w.r.t. 1 kHz 1.0 dB3.1.8 Total Harmonic Distortion(a) 1 kHz at +8 dBu 2.5%(b) 80 Hz at +8 dBu 2.5%3.1.9 Signal/Noise Ratio(a) Weighted, Random, Peak 42 dB(b) Unweighted, Random, Peak 46 dB3.1.10 Interchannel Crosstalk(a) 40 Hz -45 dB(b) 40 Hz - 125 Hz oblique segment(c) 125 Hz - 10 kHz -55 dB(d) 10 kHz - 15 kHz oblique segment(e) 15 kHz -45 dB(f) 15 kHz - 80 kHz -35 dBA profile is shown in Reference Section, Ref. 19 (c)3.1.11 Wow and Flutter 0.1%

DUAL CHANNEL SOUND RECORDING3.1.12 Level Difference Between A and B Channels(a) 40 Hz - 15 kHz 2.0 dB(b) 125 Hz - 10 kHz 1.0 dB3.1.13 Crosstalk Between A and B Channels(a) 40 Hz -20 dB(b) 40 Hz - 125 Hz oblique segment(c) 125 Hz - 10 kHz -40 dB(d) 10 kHz - 15 kHz oblique segment(e) 15 kHz -30 dBA profile is shown in Reference Section, Ref. 19 (d)3.1.14 Phase Difference Between A and B Channelsaverage:(a) 40 Hz 30(b) 40 Hz - 200 Hz oblique segment(c) 200 Hz - 4 kHz 15(d) 4 kHz - 15 kHz oblique segment(e) 15 kHz 30



peak:(a) 40 Hz - 15 kHz 40(b) 200 Hz - 4 kHz 20A profile is shown in Reference Section 2, Ref. 19 (h)

3.2. RECOMMENDED TEST METHODS (COMPOSITE RECORDERS)

VIDEO MEASUREMENTS

3.2.2 Output Signal Level

(a) Signal Level Adjustment ErrorA recording is made of the 2T Pulse and Bar signal shown in the Reference Section, Ref. 1. afteradjustment of the bar amplitude to 700 mV at the generator output. The tape is replayed and theamplitude of the bar centre at the output of the VTR, expressed as a percentage of 700 mV, is taken asthe signal level adjustment error.

(b) Gain StabilityThe greatest change occurring in the output level over a period of 1 hour, using the same recording.

3.2.3 Linear Distortion

(a) 2T Pulse-to-Bar RatioThe signal should be the 2T Pulse-and-Bar waveform as shown in Reference Section, Ref. 1.

The K rating of the pulse-to-bar ratio is defined as:-

%1004

xP

PBK =

Where B and P are the amplitudes of the bar and pulse respectively.


When the waveform is subject to line tilt or an extended distortion of the leading edge at the top of thebar, the amplitude of the bar must be measured at its mid-point after first setting the blanking levelmid-way between two successive bars to 0%.

(b) 2T Pulse ResponseThe test signal should be the 2T Pulse-and-Bar waveform as shown in Reference Section, Ref. 1.Measurement may be made using a graticule such as that shown in Reference Section, Ref. 4

If this graticule is used, the vertical gain of the oscilloscope is adjusted to make the pulse amplitude100% and then the vertical shift moved to bring the banking level onto the base line at 30%. Thehorizontal gain is advanced and the horizontal shift adjusted to make the waveform touch the H.A.Dmarkers on the 80% line. With normal gain the graticule markers are 2% K and 4% K. For 1% K and2% K the calibrated vertical gain is advanced by x2. For limits of % K and 1% K the pulse amplitudeis first set to 80% and the calibrated vertical gain then advanced by x5.

c) 2T Bar ResponseThe test signal should be the 2T Pulse-and-Bar waveform as shown in Reference Section, Ref. 1.



The horizontal timebase of the oscilloscope is adjusted so that the half amplitude points of the barreach the outer limits marked on a graticule such as that shown in Reference Section, Ref. 4.

Ignoring the first and last 2.5% (0.625ms) of the bar, the deviation from its mid-point, expressed as apercentage of its amplitude at that point, is the K rating of the bar. Measurements are made using onlyhalf the bar, the worse half being quoted as the result. It is incorrect to measure the whole bar tilt anddivide by two to obtain the K rating.

(d) 50 Hz Square Wave ResponseThe test signal should be the 50 Hz square wave test signal as shown in Reference Section, Ref. 5, butwith added field synchronising pulses.

With the horizontal scan at field rate the 50 Hz signal is adjusted as in 3.2.3(c). For a stationary displaythe signal must contain field synchronising pulses. Again, ignoring the first and last 2.5% (250 ms), thepercentage deviation of the worse half divided by 2 is the K rating of the bar. (It may be noted that forthe same deviation on the display a 4% K figure for the bar response looks the same as 2% K for50 Hz).

(e)(f) Chrominance/Luminance Gain and delay InequalityThe measurements are made using a 2Tc composite Pulse-and-Bar signal (Reference Section, Ref. 6a)with the output of the recorder under test fed to a Gain and Delay test set where available. The outputof the test set is viewed on an oscilloscope and the test set is adjusted to make the envelope of thechrominance pulse flat along the baseline. If a test set is not available then the level of distortionshould be estimated

By examining the sinusoidal distortions at the bottom of the 2Tc composite pulse on a waveformmonitor or oscilloscope. The method is described in Part B.

It should be noted that if Chrominance/Luminance crosstalk is present the above method forgain inequality will produce an erroneous result. The measurement is best made using the 2Tc non-composite waveform (Reference Section, Ref. 6b). The 50% luminance pedestal is used to calibratethe vertical gain of the oscilloscope and the chrominance amplitude is measured directly.

3.2.4 Non-Linearity Distortion

(a) Luminance Line Time Non-LinearityThe test signal consists of a 5-step staircase (Reference Section, Ref. 2) occupying one line in everyfour, followed by three lines of black or white. Measurements are made with three lines of white (baron) and with three lines of black (bar off) and the worst result quoted.

The output signal is passed through a suitable differentiating network (Reference Section, Ref. 3),amplified and displayed on an oscilloscope. The result is a train of five pulses. Non-linearity ismeasured as the difference in amplitude between the largest and the smallest expressed as a percentageof the largest.

i.e. %100max

minmax xE

EE

(b) Differential PhaseThe test signal should be a 5 step staircase with added subcarrier (Reference Section, Ref. 2)

The differential phase may be measured by using a vectorscope in the line-time mode. The six sectionsof subcarrier are compared for their phase relationships taking the blanking level section as areference. The differential phase is defined as the largest departure in phase form that reference.Measurements are made with the white bar on and with the white bar off and the worst measurement isquoted.



(c) Differential GainThe test signal should be a 5 step staircase with added subcarrier (Reference Section, Ref. 2)

The differential gain may be measured by using a vectorscope in the line-time mode. The six sectionsof subcarrier are compared for their amplitude relationships and taking the blanking level section as areference, the differential gain is defined as the largest departure in amplitude from that of thereference expressed as a percentage. Measurements are made with the white bar on and with the whitebar off and the worst measurement is taken as the result.

The measurements in paragraph 3.2.4 (a) and (b) are difficult to make accurately on a VTR due to thepresence of noise, moire and jitter. More accurate measurements can be made using a suitable non-linearity test set, preferably one which integrates the measurement and has a line strobe facility. Someimprovement can also be obtained by using a 200 kHz low-pass filter in the display circuit of avectorscope.

3.2.5 NoiseNoise measurements should be made using a 50% pedestal test signal.

When measurements are made on equipment incorporating digital timebase correctors the pedestallevel may be adjusted slightly to minimise the effects of quantisation noise.

(a) Weighted LuminanceMeasurement is made in the band 10 kHz (7.5 kHz) - 5.0 MHz using RMS detection. Thecharacteristic of the luminance weighting filter is shown in Reference Section, Ref. 7.

(b) Weighted ChrominanceMeasurement is made in the band 3.5 MHz - 5.5 MHz as defined only by the characteristic of theweighting filter as shown in Reference Section, Ref. 7 and using RMS detection.

(c) Total LF Random and PeriodicThe total LF noise should be measured peak-to-peak in the frequency band 40 Hz -10 kHz (7.5 kHz).

(d) Moire and Chrominance Modulation NoiseNoise measurements are made using 100% colour bars as the test signal (Reference Section, Ref. 8).The VTR replay output is fed to a PAL decoder and the RED output measured on an RMS noisemeasuring set over a frequency band of 0 - 3 MHz. The figure obtained is increased by 8 dB to convertto peak-to-peak and to allow for the weighting of the decoder. Each colour bar is sampled in turn in themiddle of the bar and the worst figure is taken as the result.

100% saturated full field Y, C, G, M, R, B colours may be used instead of colour bars.

Moire may also be measured on a spectrum analyzer. An assessment of the combined effect can beobtained by a square law addition of the individual components.

AUDIO MEASUREMENTS

3.2.6 Output Signal Level(a) Signal level at output after line-up using the EBU alignment tape or a recording made to the

same standard.

(b) Gain StabilityThe greatest change occurring in the output level over a period of 1 hour, using the same recording.



3.2.7 Amplitude/Frequency ResponseThe input level to the recorder should be -10 dBu. As this test is a measurement of the variation of gainof the equipment with frequency, corrections should be made for any variation of the input level withfrequency.

Tests should be made at the following frequencies and the measurements should be referenced to thelevel at 1 kHz:-

40 Hz, 60 Hz, 125 Hz, 250 Hz, 500 Hz,

1 kHz, 2 kHz, 4 kHz, 6 kHz, 8 kHz,

10 kHz, 12 kHz, 15 kHz,Additional tests should be made to ensure that the overall response falls off smoothly outside thefrequency band.

3.2.8 Total Harmonic DistortionThe input level to the VTR should be +8 dBu at each frequency.

3.2.9 Signal/Noise RatioThe noise levels are measured using a test set incorporating a standard PPM (to BS 6840), and a lownoise amplifier with calibrated variable gain. The 'unweighted' bandwidth is constrained in accordancewith ITU-R BT.468-4, shown in Reference Section, Ref. 9(a), and the 'weighted' frequency response isdetermined by the ITU network as defined in ITU-R BT.468-4 shown in Reference Section, Ref. 9(b).

With the VTR under test lined up to its normal gain setting, it is first supplied with 1 kHz tone at0 dBu and a recording is made. The input signal is then replaced by a 600 ohm termination and afurther recording is made. The output of the VTR is connected to the test set and the recordings playedback. The gain of the test set is adjusted so that, on the first recording, the PPM gives a scale readingof '4' (i.e. 0 dBu); with the second recording, the gain of the test set is re-adjusted so that the PPMagain peaks to a scale reading of '4'. The signal/noise ratio is the difference between the two settings ofthe test set gain.

3.2.10 Interchannel CrosstalkThis test is intended to measure the crosstalk performance from unrelated tracks such as those used fortimecode and unrelated audio signals.

The test signals at a level of -10 dBu should be fed to tracks likely to cause interference to the trackbeing measured. The input to the track being measured should be terminated in 600 ohms. Upon replayof the recorded signals the crosstalk is determined from the difference in measured level of the twotracks under consideration.

As crosstalk performance can approach, or be better than, the noise performance in tape recorders, itmay be necessary to employ selective filtering in this measurement.

A profile is shown in Reference Section, Ref. 19 (c)

3.2.11 Wow And FlutterMeasurements are made by first recording a test frequency of 3.15 kHz at standard reference level. Onreplay wow and flutter amplitudes should be measured using an instrument complying with IECPublication 386, the relevant details of which are given in Reference Section, Ref. 10.



DUAL CHANNEL SOUND RECORDING

3.2.12 Level Difference Between A and B ChannelsTest signals (initially at 1 kHz) from a common source at a level of -10 dBu should be fed into theequipment under test. The output levels from the A and B channels on the replay should be measuredat frequencies between 40 Hz and 15 kHz and the differences calculated.

3.2.13 Crosstalk Between A and B ChannelsTest signals (initially at 1 kHz) at a level of -10 dBu should be fed into one input of the recorder, and a600ohm termination connected to the other. The Crosstalk is calculated from the measured outputs ofthe A and B channels. Measurements should be made at frequencies between 40 Hz and 15 kHz.

The measurements should be repeated with the input signals reversed.

As crosstalk performance can approach, or be better than, the noise performance in tape recorders, itmay be necessary to employ selective filtering in this measurement.

A profile is shown in Reference Section, Ref. 19 (d)

3.2.14 Phase Difference Between A and B ChannelsTest Signals (initially at 1 kHz) from a common source at a level of -10 dBu should be fed into theequipment under test. The phase difference between the outputs form the A and B channels on replayshould be measured at frequencies between 40 Hz and 15 kHz. When the difference is not constant,the mean difference is taken as the result, though a note should be made of the maximum difference aswell.

A profile is shown in Reference Section, Ref. 19 (h)

3.3 PERFORMANCE FIGURES (COMPONENT RECORDERS)This section gives the performance figures for component VTRs:

The figures refer to a single recording and replay not necessarily on the same machine.

When more than one head is used each head should perform within the given limits.

3.3.2 Signal Levels(a) Signal Level (Adjustment Error) 0.7V (2%)(b) Signal Level Gain Stability (over 1 hour) 2%(c) Interfield Flicker : Luminance 1%

Chrominance 2%

3.3.3 Linear Waveform Distortions (2T Pulse and Bar in Luminance and 5T Pulse and Barin Colour Difference Channels)

Y Pr & Pb(a) Pulse-to-Bar Ratio 1.5% K 2.0% K(b) Pulse Response 1.5% K 2.0% K(c) Bar Response 1.5% K 1.5% K(d) 50 Hz Square Wave Response 1.5% K 1.5% K3.3.4 Delay Inequality between all Component Channels(a) Mean Timing difference 20 ns(b) Timing perturbations (p-p) 10 ns



3.3.5 Non-Linear Waveform Distortions(a) Amplitude Non-Linearity 4%(b) Component Crosstalk -43 dB3.3.6 Noise(a) Weighted Luminance (RMS) -52 dB(b) Colour Difference (RMS) 1.6 MHz low pass filter -48 dB(c) Total Low Frequency in Luminance channel (p-p) -45 dB(d) Total Low Frequency in Colour Difference Channels (p-p) -43 dB

3.4 RECOMMENDED TEST METHODS (COMPONENT RECORDERS)

3.4.1 Test ConditionsThe analogue component signals (Y, Pr and Pb) will be related to the colour separation signals (R, Gand B) by the following matrix equations.

Y 0.299 0.587 0.114 RPb = -0.169 -0.331 0.500 . GPr 0.500 -0.419 -0.081 B

The colour separation signals have normal peak amplitudes of 700 mV. Synchronising signals may beadded to or kept separate from the luminance component.

The following methods are relevant when component recorders are being measured and it may beconvenient to use a waveform monitor capable of displaying the three components simultaneously:

3.4.2 Signal Levels

(a) Signal Level Adjustment ErrorA recording is made of the Pulse and Bar signals shown in the Reference Section, Ref. 1 afteradjustment of the bar amplitudes to 700 mV at the generator output. The 2T signal is fed to the Ychannel and the 5T signal is fed to Pr and Pb. The tape is replayed and the amplitude of the bar centreat the output of each of the component channels, expressed as a percentage of 700 mV, is taken as thesignal level adjustment error.

In some cases the "Lightning" method of measurement described in Part B Guidelines may be useful.

(b) Gain StabilityThe greatest change occuring in the output level of each channel over a period of 1 hour, using thesame recording.

(c) Interfield FlickerThe odd and even fields of each component channel are examined separately and the maximumamplitude difference between the two fields, expressed as a percentage of 700 mV, is taken as theflicker.

3.4.3 Linear Waveform DistortionsLinear waveform distortions (a) to (c) are measured using the 2T Pulse and Bar test signal in the Y(luminance) channel and the 5T Pulse and Bar test signal in the Pr and Pb (colour difference) channels.The waveforms are shown in the Reference Section, Ref. 1.



(a) Pulse-to-Bar RatioThe pulse-to-bar K rating is defined as:

%1004

xP

PBK =

where B and P are the amplitudes of the bar and pulse respectively.

In practice, the pulse will be taken as the reference during measurement.


When the waveform is subject to line tilt or an extended distortion along the leading edge at the top ofthe bar, the amplitude of the bar must be measured at its mid-point after first setting the reference level(blanking for Y) mid-way between two successive bars to 0%.

(b) Pulse ResponseMeasurement may be made using a graticule such as that shown in the Reference Section, Ref. 4.

The vertical gain is adjusted to make the pulse amplitude 100% and then the vertical shift moved tobring the reference level (blanking for Y) onto the baseline at 30%. The horizontal gain is advancedand the horizontal shift adjusted to make the waveform touch the H.A.D. markers on the 80% line.With normal gain the graticule markers are 2% K and 4% K. For 1% K and 2% K the calibratedvertical gain is increased by x2. For 0.5% K and 1% K the pulse amplitude is first set to 80% and thecalibrated vertical gain is increased to x5.

If it is desired to measure the K rating exactly, the variable vertical gains should be adjusted until theworst pulse overshoot just touches the inner limits. The calibration gain is then returned to normal andthe amplitude of the pulse measured (P%) then

%200GainCalibratedxP

K =

This is illustrated in the following table:


57.5 0.7% K50 0.8% K

(c) Bar ResponseThe horizontal timebase of the waveform monitor or oscilloscope is adjusted so that the half amplitudepoints of the bar reach the outer limits marked on a graticule such as that shown in the ReferenceSection, Ref. 4.

Ignoring the first and last 2.5% (0.625ms) of the bar, the deviation from its mid-point, expressed as apercentage of its amplitide at that point, is the K rating of the bar. It must be emphasised thatmeasurements are made using only half the bar, the worst half being quoted as the result. It is wrong tomeasure the whole bar and divide by two to obtain the K rating.



(d) 50 Hz Square Wave ResponseThe test signals are the 50 Hz square waves shown in the Reference Section, Ref. 5. The 0V to700 mV signal is used in the Y channel and the -350 mV to +350 mV signal is used in the Pr and Pbchannels.

With the horizontal scan at field rate the 50 Hz signal is adjusted to coincide with the appropriate barmarkings on the graticule. For a stationary display the signal must contain field synchronising pulses(Y) or the waveform monitor must be externally triggered from the same synchronising pulses (Pr andPb). Ignoring the first and last 2.5% (250 ms) of the bar, the percentage deviation of the worst halfdivided by two is the K rating of the bar. (It may be noted that for the same deviation on the display a4% K figure for the bar response looks the same as a 2% K figure for 50 Hz).

3.4.4 Delay Inequality

(a) Timing DifferencesThe test signal consists of sinusoids as shown in the Reference Section, Ref. 20 where the frequency ofthe sinusoid applied to the luminance channel is 500 kHz and that to the colour difference channels is502 kHz. When these signals are subtracted a null appears half way along active line time giving theappearance of a "bowtie". A timing difference in the components gives rise to a positionaldisplacement of the null by 1ms for about 4ns of timing error. Markers on some of the picture linesenable a direct reading of any timing errors to be made. The method is not well suited for showingtiming differences that are not constant throughout the line time.

In this situation, or when there is noise or the sine waves are distorted, a dual channel oscilloscopewith delayed timebase and writing speed in the order of 20 ns per division should be used to comparethe coincidence of rising or falling slopes of the sine waves shown in the Reference Section, Ref. 20.

The delaying timebase should be triggered from the rising edge of the luminance pedestal so that Prand Pb can be compared with Y. High gain should be used in the vertical amplifiers to give a steepslope to the edges being measured and the oscilloscope delay time multiplier control used to inspectthe full line period. The worst error should be quoted.

The tracking of the oscilloscope input amplifier controls can be checked using the staircase at the startof the waveform, the step amplitudes being designed to match the 5, 10 and 20 mV per divisionsequence of many general purpose instruments. When this method is used, it is also beneficial if somelines of the test signals are left unmodulated to give a line through the sine wave crossings, aiding thevertical positioning of the traces at high magnifications.

If a high speed oscilloscope is not available, an estimate can be made using matched and calibratedswitchable delays in both oscilloscope inputs (to account for insertion delay) and adjusted for a visualtiming null. Again this should be checked across the line period.

In some cases the "Lightning" method of measurement described in Part B Guidelines may be useful.

(b) Timing PerturbationsIn component analogue television tape recorders, time division multiplex techniques are used to sharethe luminance and colour difference signals between the recording channels and, as a consequence ofthis, the three component signals are not recorded simultaneously. In replay this gives rise to to timingdifferences between the signals in addition to the absolute timing jitter. Even after timebase correctionit is likely that some errors will remain.

Timing perturbations can be measured using any of the methods described for Delay Inequality in3.4.4 (a). In all cases the oscilloscope should be externally triggered from the studio reference pulses.



3.4.5 Non-Linear Waveform Distortion

(a) Amplitude Non-LinearityThe waveforms used are ramp signals shown as typical examples in the Reference Section, Ref. 21. Inorder that the system may be tested under a wide range of APL, the signal should consist of 6 lines oframp in every 24, with the intervening lines at black or white. Measurements are made with 18 lines ofwhite (bar on) and then 18 lines of black (bar off) and the worst result quoted.

To make the measurement, the output of the appropriate component channel is differentiated by asuitable network as in the Reference Section, Ref.3 and the mid-point of the resultant signal level madeto occupy 100% on an oscilloscope. The error is then the peak-to-peak percentage deviation over theduration of the differentiated ramp.

If significant noise is present, making the assessment of non-linearity difficult and the ramp waveformshave been inspected to ensure that there are no quantisation errors, then staircase waveforms similar tothose shown in the Reference Section, Ref. 22 may be used. The signal should consist of 6 lines ofstaircase in every 24 with the intervening lines at black and white. Measurements are made with 18 linesof white (bar on) and then with 18 lines of black (bar off) and the worst result quoted.

On replay the signal is passed through the differentiating network and displayed on an oscilloscope toshow a train of five pulses. Non-linearity is given by the difference in amplitude between the largestand smallest pulse expressed as a percentage of the largest.

i.e. %100max

minmax xE

EE

NOTE: Some waveform monitors may have insufficient gain to achieve 100% amplitude when a linerate ramp such as that shown in Ref. 21 is differentiated. In cases such as these, the rampsignals provided as `valid' waveforms from Component Test Signal Generators may be used,as the shorter duration of these ramps give a larger amplitude pedestal when differentiated.Alternatively, the line rate signal may be used as for the case when noise is present.

(b) Component CrosstalkRecordings are made with two of the component channels energised with the multiburst test signalsshown in the Reference Section, Ref. 23 and the crosstalk into the "dormant" third component ismeasured peak-to-peak. The result is expressed in dB relative to 700 mV.

3.4.6 NoiseMeasurement is made using a 10% lift signal. Care should be taken that the noise of the generatedsignal is not significant. When measurements are made on VTRs containing digital processingequipment the 10% lift signal may be adjusted slightly to minimise the effects of quantisation noise.

(a) Weighted LuminanceMeasurement is made on the Y channel in the band 10 kHz (7.5 kHz) - 5.0 MHz using RMSdetection. The characteristic of the luminance weighting filter is shown in the Reference Section,Ref. 7.

(b) Colour Difference NoiseMeasurement is made on the Pr and Pb channels in the band 10 kHz -1.6 MHz using rms detection. TheColour Difference filter having the characteristic shown in the Reference Section, Ref. 24 should beused. Note that this network has a 6 dB insertion loss and therefore the measured figure should becorrected accordingly.



(c) Total Low Frequency Noise in Luminance ChannelMeasurement is made unweighted in the band 40 Hz - 10 kHz (7.5 kHz) using peak-to-peak detection.

(d) Total Low Frequency Noise in Colour Difference ChannelsMeasured the same as in the Luminance Channel.

Section 4: Audio Recorders On-line version source EBU website


SECTION 4AUDIO RECORDERS

4.1. PERFORMANCE FIGURES

4.1.1 Definitions and Operational PracticesThis section is applicable to all recording media including hard disc recorders, sprocketed soundfollowers, high quality tape recorders and less high quality tape equipments.

"High quality" tolerances apply to equipments, including multi-track recorders, used for the recordingand replaying of significant speech and music.

"Less high quality" applies to audio cartridge equipment for NAB type B audio cartridges or similarequipment used for effects.

Tolerances listed refer to a single recording and replay not necessarily on the same machine.

Tape recorders and reproducers should preferably employ ITU/IEC equalisation characteristics inaccordance with IEC Publication 94, 3rd Edition 1968.

Related tracks are defined as those which normally carry specific contributions to a composite sound,such as the orchestral components of a musical balance.

Unrelated tracks are defined as those carrying information which is acoustically dissimilar, such astime-code or other synchronising signals, effects and foreign language tracks.

SoundFollowers

HighQuality

Less HighQuality

4.1.2 Output Signal Level(a) Insertion Gain Adjustment Error 1.0 dB 1.0 dB 1.5 dB(b) Gain Stability 0.5 dB 0.5 dB 1.0 dB4.1.3 Amplitude/Frequency Response(a) 40 Hz to 15 kHz w.r.t. 1 kHz 1.5 dB 1.5 dB 2.0 dB(b) 125 Hz to 10 kHz w.r.t. 1 kHz 1.0 dB 1.0 dB 1.5 dB4.1.4 Signal/Noise Ratio(a) Weighted, Random, Peak 42 dB 42 dB 38 dB(b) Unweighted, Random, Peak 46 dB 46 dB 42 dB4.1.5 Interchannel Crosstalk(a) 40 Hz -45 dB -45 dB -45 dB(b) 40 Hz - 125 Hz oblique segment(c) 125 Hz - 10 kHz -55 dB -55 dB -55 dB(d) 10 kHz - 15 kHz oblique segment(e) 15 kHz -45 dB -45 dB -45 dB(f) 15 kHz - 80 kHz -35 dB -35 dB -35 dBA profile is shown in Reference Section, Ref. 19 (c)4.1.6 Timecode Crosstalk

500 Hz - 20 kHz - -65 dB -

Section 4: Audio Recorders On-line version source EBU website

ITC Handbook of Technical Standards for Television Programme Production Issue

Handbook Tech Standar Tv Production

Documents

Transcript of Handbook Tech Standar Tv Production