Sistem Transmisi Radio

TE-09-13132 sks

Tim Bidang StudiTelekomunikasi Multimedia

(Achmad Ansori, Devy Kuswidiastuti, Gatot Kusrahardjo, M Aries Purnomo)

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Radiocommunication :Telecommunication by means of radio waves.

radio waves, hertzian waves :An electromagnetic wave propagated in space without artificial guide and having by convention a frequency lower than 3.000 GHz.

Note  : The electromagnetic waves having frequencies around 3 000 GHz may be regarded either as radio waves or optical waves.

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Radio :Pertaining to the use of radio waves.

(Radio) station :One or more transmitters or receivers of a combination of transmitters and receivers, including the accessory equipment, necessary at one location for carrying on a radiocommunication service, or the radioastronomy service.

Note 1  : In the RR, each station shall be classified by the service in which it operates permanently or temporarily.

Note 2  : Radiocommunication service :A service as defined in the RR involving the transmission, emission and/or reception of radio waves for specific telecommunication purposes.

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Space StationEarth StationTerrestrial StationMobile StationLand StationBroadcasting Station

Transmitter Block Diagram

Signal

SourceModulator

Power

Amplifier

AntennaSpeechMusicVideoData

Sound Broadcasting Service (analog / digital)Televisio Broadcasting Service (analog / digital)

Bandwidth

Definisi:

Bandwidth adalah range antara frekuensi

terendah dan frekuensi tertinggi

Contoh:

f1 f2 f

dimana:

f1: frekuensi terendah

F2: frekuensi tertinggi

BW = f2 – f1

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necessary bandwidth :For a given class of emission, the width of the frequency band which is just sufficient to ensure the transmission of information at the rate and with the quality required under specified conditions.

occupied bandwidth :The width of a frequency band such that, below the lower and above the upper frequency limits, the mean powers emitted are each equal to a specified percentage β/2 of the total mean power of a given emission.

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Speech : 300 -3.400 HzMusic : s/d 15 kHzVideo : 4 s/d 5 MHz

Carrier :An oscillation or wave, usually periodic, some characteristic of which is intended to be constrained by modulation to follow the values of a signal or of another oscillation.

Modulation :A process by which a quantity which characterizes an oscillation or wave follows the variations of a signal or of another oscillation or wave.

Antenna :The antenna converts a current or a voltage signal to an electromagnetic signal which is radiated throughout space.

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BAND• LF Broadcasting (band 5)• MF Broadcasting (band 6)• HF Broadcasting (band 7)

• FM-VHF Broadcasting (band 8)87,5 – 108 MHz

• VHF Television Broadcasting (band I & III)174 – 223 MHz

• UHF Television Broadcasting (band IV & V )478 – 606 MHz & 606 – 806 MHz

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ITU-R BT-470-6VHF Band : 7 MHzUHF Band : 8 MHz

TV Channel Spacing

Receiver Block Diagram

RFAmplifier

IFMixer

IFAmplifier

EnvelopeDetector

AudioAmplifier

Antenna

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The IF Mixer shifts its input in the frequency domain from the carrier frequency to an intermediate frequency.

AM Broadcasting Receiver : 455 kHzFM Broadcasting Receiver : 10,7 MHzTV Broadcasting Receiver ( analog ) : 33,4 MHz untuk sound channel 38,9 MHz untuk video channel

Circuit Level ModelEnvelope Detector

+

-R C

+

-VoutVin

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Transmisi Gelombang Mikro

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Radio-relay systemRadiocommunication system in the fixed service operating at frequencies above about 30 MHz which uses propagation in the atmosphere and which may include one or more intermediate stations

NOTE 1 : The term “radio-relay system”, found in a number of ITU-R Recommendations, can refer, in certain cases, to both radio-relay systems, as defined above, and other types of systems in the fixed service.

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Trans-horizon radio-relay system :Radio-relay system using trans-horizon tropospheric propagation, mainly forward scatter.

NOTE 1 : Recommendation ITU-R P.310 gives a definition for trans-horizon (tropospheric) propagation.

Radio link :A telecommunication facility of specified characteristics between two points provided by means of radio waves.

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total loss (of a radio link) : (Symbols: Ll or Al)The ratio, usually expressed in decibels, between the radio-frequency power supplied by the transmitter of a radio link and the radio-frequency power supplied to the corresponding receiver in real installation, propagation and operational conditions.

free space basic transmission loss : (Symbols: Lbf or A0)The transmission loss that would occur if the antennas were replaced by isotropic antennas located in a perfectly dielectric, homogeneous, isotropic and unlimited environment, the distance between the antennas being retained.

Note : If the distance d between the antennas is much greater than the wavelength λ, the free space attenuation in decibels will be:

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Repeater station (point-to-point) :A station where the payload is passed through mainly transparently.

Repeaters could be “non-regenerative” when the signal is only filtered and amplified, with or without down and up conversions (e.g. in some analogue FDM systems) or “regenerative” when, indigital applications, the signal is demodulated and re-modulated before transmission to the next radio hop.

Passive repeaters implemented without any active radio component (e.g. two-directional antenna connected back-to-back, reflector, etc.) are also utilized.

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Drop-insert (of a payload)A functionality provided in analogue and digital repeaters, where only radio-system specific control and service channels and possibly part of the payload is made available for local traffic and system management and maintenance.

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Trans-horizon radio-relay system