MAYURBHANJ SCHOOL OF ENGINEERING � LAXMIPOSI ,BARIPADA,757107
FM Transmitters
Crystal
oscillator
phase modulator
frequency multiplier
Power amplifier
Audio source
NBFM
WBFM
ANTENNA
Crystal oscillator-
Crystal oscillator generates the stable carrier signal.
phase modulator-
The phase modulator modulates the carrier signal and the massage signal in the low power range to generate a narrowband FM.
Frequency multiplier-
The frequency multiplier is used to increase the frequency deviation and carrier signal frequency to a desired level.
Power amplifier-
The power amplifier gives the required power level to the signal which passes through the antenna.
Antenna-
Antenna is a device which is used for sending and receiving the information.
FM Receiver
RF
tuned amp
mixer
IF
tuned amp
limiter
Discrimi- nator
Local oscillator
Delayed AGC
AFC
Vol. & TONE
control
De-
emphasis
Power
amp.
RF tuned amplifier-
These amplifiers are used for impedance matching to minimise noise level
Mixers-
These oscillator circuits are take any form to mix up the frequency modulated signal for performing the operation in such circuit central frequency are change but deviation are constant
Intermediate frequency amplifier-
The IF amplifier provides most of the gain and bandwidth requirement of the receiver.
Limiters-
Limiters are those circuit which allows the certain frequency
range to pass out and block the other signals
Discriminator-
The discriminator change FM into AM. A simple diode detection then recover the intelligence contained in the envelop of the AM waveform.
De-emphasis-
The artificial boosting given to the higher modulating frequencies in the process of pre-emphasis is nullified or compensated at the receiver by the process of De- emphasis
Vol & tone controller-
In this circuit it control the efficiency of audio signal. The signal whose efficiency is more then audible range are neglected in this circuit.
Power amplifier-
The power amplifier gives the required power level to the signal which passes through the loudspeaker.
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