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FUNCTION GENERATOR

OPERATION MANUAL

INDEX

1. Introduction ………………………………………… (3)

2. Specifications ………………………………………… (3)

3. Working Theory ……………………………………… (7)

4. Structure ……………………………………………… (8)

5. Operation & Maintenance …………………………… (9)

6. Accessories ………………………………………… (14)

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This instrument is a highly stable, multipurpose, broad bandwidth

function generator, which can directly generate Sine, Triangle,

Square, Ramp, Pulse waveforms as well as Linear & Logarithm

Sweep signals. Application of Single-chip-machine intelligently

controls all of the functions, displays and indicators, which allow

users to know about the working status of the instrument easily

and accurately.

1. Specifications

1.1 Frequency Range: 0.6Hz-6MHz

1.2 Waveform:

Sine, Triangle, Square, Positive & Negative Ramp,

Positive & Negative Pulse. Symmetry of Ramp and Pulse

is variable within 80:20 (1Hz~100kHz)

1.3 Sine Waveform:

1) Distortion: ≤1% (0.1Hz~100kHz)

2) Frequency Response: ≤±0.5dB(0.1Hz~100KHz);

≤±1dB(3MHz)；

≤±2dB(6MHz)；

1.4 Rising/Falling Edge of Square Waveform: ≤50ns

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1.5 TTL Output:

1) Higher Level ≥2.4V, Lower Level ≤0.4V, capable

of driving 20 TTL loads.

2) Rising time: ≤30ns

1.6 Output:

1) Impedance: 50Ω±10%

2) Output Amplitude: ≥20Vp-p (open circuit),

3) Output Attenuator: 20dB, 40dB, 60dB

4) DC Offset: 0 ~±10V adjustable

5) Display Error of Amplitude: ±10% ±2 digits

(output level higher that 1/10 of full scale)

1.7 Power Output:

1) Amplitude: ≥20p-p

2) Output power: Max. 5W

1.8 VCF Input:

1) Max. Voltage: -5V~0V ±10%

2) Max. Control rate: 1000:1

3) Frequency: DC~1kHz

1.9 Amplitude Modulation:

1) Carrier Bandwidth:

2) Modulation Freq.: 400Hz (INT), 0~1MHz (EXT)

3) Modulation Depth: 0~85%

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1.10 Frequency Modulation:

1) Deviation: 0 ~ 10%

2) Modulation Freq.: 400Hz(INT), 0 ~ 20kHz (EXT)

3) Distortion: ≤ 1.5% ( fc=500kHz, fm=1kHz, 10%)

1.11 Sweep

1) Sweep mode: Linear, Logarithmic.

2) Sweep time: 10ms~5s

3) Sweep rate: 1000:1

4) Output Amplitude: 7Vp-p

5) Output Impedance: 600Ω

1.12 Frequency Counter:

1) Measuring Range: 1Hz-20MHz

2) Input Impedance: 1MΩ / 20pF

3) Sensitivity: 10mVrms

4) Max Input: 150V AC+DC (with attenuator)

5) Input attenuator: 20dB

6) Measuring Error: not more than 3×10-5 ±1 digit

1.13 Power Supply

1) Voltage: AC 220V ± 10%

2) Frequency: 50Hz±2Hz

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1.14 Operating Ambient:

1) Temperature: 0°C~40°C

2) Humidity: ≤RH 90%

3) Atmospheric Pressure: 86kPa~104kPa

1.15 Dimension (mm): 290L × 260W × 90H

1.16 Weight: 3kg

2. Working Theory

Figure 1

2.1 Waveform Generator Circuit

This segment is consisted of MAX038 Function Generator,

Frequency & Duty Rate control circuits. Waveforms are

selected by SCM.

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2.2 SCM (Single-chip-machine) Circuit

This segment is consisted of SCM 89C52, Panel Input,

Frequency & Amplitude Display and Output & Indicator

circuits. The main jobs are: Control waveform of output

signal; Test and display the frequency of output or external

input signal; Display amplitude of output waveform.

2.3 Frequency Counting Circuit:

It is consisted of Broad-banded Amplifier and

Square-waveform Regulator, which external signal will go

through.

2.4 Power Amplifier

In order to insure the stability and high slew rate, dual

channel power amplifier is employed. The entire amplifier is

with the characteristic of phase inversion.

2.5 FM Mode

When SWP/FM switch being pressed down and MOD

switch is pulled up, a 1KHz modulation signal which

generated by RC oscillator is applied to VCF end.

2.6 Power Supply

Four sets of power supply, ±23V/±15V/±5V/+5 are

employed. ±23V is used for Amplifier. ±15V and ±5V are

used for Waveform Generator. +5V is mainly for SCM circuit.

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3. Structure

This instrument has an all-metal frame and cover, plastic

front panel with a elegant and small-sized appearance. Most

of the components (including switches and knobs) are fixed

on two PCBs. All adjustable components are located at an

easy-to-adjust position. Only to unscrew the back panel and

remove the cover up and down when the instrument need to

be adjusted or repaired.

4. Operation and Maintenance

4.1 Symbols and functions in front panel and rear panel:

See Table 1, Figure 2 and Figure 3.

Figure 2

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Table 1

NO SYMBOL DESCRIPTION OPERATION

1 POWER Power Switch Push down, power on

2 △ Frequency Range

Selection

Press the key, the multiples of freq. will be changed

from low to high. Collaborate with Knob “19” to set

output frequency.

3 ▽ Frequency Range

Selection

Press the key, the multiples of freq. will be changed

from high to low. Collaborate with Knob “19” to set

output frequency.

4 Waveform Selection

Press the key to change output waveform. Work

with knob “17” and key “18”, polarity of ramp and

pulse can be selected.

5 DC OFFSET DC Offset Press button. Indicator lights when the function is

activated.

6 DC Offset Knob DC output can be adjusted with from

-10V~+10V(Output waveform is 5Vp-p)

7 MODE

Linear/Logarithmic

/External Sweep

selection

Sweep mode will change in sequence each time the

button is pressed.

8 SPEED Sweep Speed Adjust the knob to change sweep speed.

9 Output Attenuator Press the button to set attenuation among 0, 20dB,

40dB and 60dB. Indicators light respectively.

10 OUTPUT Voltage Output Output terminal of waveforms, max. output 20Vp-p

with impedance of 50Ω.

11 AM/FM AM/FM Adjustment

Activate modulation mode with button “24”. If the

knob is Pull-out position, the instrument is in AM

mode, modulation depth can b adjusted with the

knob. If the knob is Push-in position, the instrument

is FM mode, frequency deviation can be adjusted

with the knob.

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12 AMPLITUDE

Output Amplitude

Adjustment

Waveform Inversion

Work with button “9” to adjust amplitude of output

waveforms.

13 INPUT Counter Input

Terminal

To test the frequency of an external signal, connect

the signal to this terminal.

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EXT

ATT20dB

LPF

Selector of

INT/EXT signal,

20dB Attenuator and

Low-Pass Filter

When external signal is selected and the signal is too

strong, press the key, 20dB attenuator is activated

with the indicator lit. Press the key again, LPF

indicator lights(with attenuator, cutoff freq. 100kHz)

About 20 seconds after no signal is detected, “0”

will be displayed.

15 WIDTH Sweep Width Use the knob to adjust sweep width when the

instrument is in sweep mode.

16 Amplitude Display

Display peak to peak value of output signal (open

circuit). If a 50Ω load is connected, actual value on

the load is 1/2 of that is displayed. If desired output

amplitude is lower than 1/10 of max. value when

amplitude knob is fully turned, connecting an extra

attenuator is advised. If the instrument is working in

AM mode, displayed amplitude is an Un-cal value.

17 SYMMETRY Symmetry Adjusting Symmetry can be adjusted from 20:80 to 80:20.

18 Symmetry

Activating Key

Press the key to activate symmetry adjusting knob.

19 Frequency

Adjustment

Turn the knob CW, output frequency is increased

and vice versa.

20 Frequency Display

Display the frequency of output signal or external

input signal. Indicator “GATE” blinks when counter

is working well. If input frequency over 20MHz,

indicator “OV.FL” will be on. Hz and kHz indicate

what units of frequency would be at the moment

when one of them turns on.

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4.2 Symbols and functions in rear panel:

Figure 3

21 Power Socket AC 220V/0.5A fuse or AC110V/1A fuse.

22 Line Voltage Selection 110V/220V switching.

23 VCF IN/EXT MOD IN/EXT

SWP IN Terminal

a) Input terminal of Voltage-Control-Frequency,

input voltage range 0~-5V.

b) Input terminal of External Modulation signal.

c) Input terminal of External Sweep signal.

A sweep signal is generated while frequency

vary along input control signal.

24 MOD ON/OFF switch of AM/FM,

INT/EXT modulation selection.

25 TTL OUT Output terminal of TTL pulse,

with impedance of 50Ω.

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4.3 Service and Calibration

This instrument can be operated continuously in proper

ambient, but you are advised to calibrate it every three

months. Calibration procedure is as:

1) Sine Distortion Calibrating:

Turn Amplitude Adjusting Knob to its max, select sine

waveform output and set frequency at 1kHz. Connect this

signal to a distortion meter. Adjust RP102 to have distortion

match technical requirement.

2) Output Amplitude Calibrating:

Set the instrument in the same working status as 1), connect

the signal to an oscilloscope. With observing peak-peak

value of the output signal, adjust RP601 to have the output

amplitude match technical requirement.

3) Frequency Calibrating:

Set frequency counter at “EXT”, connect a 10MHz signal of

standard oscillator to the input terminal. Adjust C607 to get

standard 9999.9kHz on the LED display. Set the amplitude

of the standard signal to 100mVrms, adjust RP401 to have

9999.9kHz stably displayed on LED.

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4.4 Trouble Shooting

Sufficient knowledge is needed when you are going to fix

problems on this instrument. Locate the problem area in

PCB by with observing the phenomenon, visual inspection

is suggested in first place, and then check the PCB in static

and dynamic mode. Replace the component which is found

broken.

5. Accessories

Operation Manual 1copy

Power Cord 1pc

Test Lead(50Ω) 1pc

BNC Cord 1pc

Fuse (0.3A) 2pcs