MINI FM STATION

                                                               ABSTRACT

The aim of this project is to transmit voice and music in FM frequency band

(88-108MHZS) similar to what an FM station does.this is possible by frequency modulating the voice or music signal with a carrier.

                        The idea is very simple,the frequency of the carrier is varied linearly in accordance with the voice or music that we want to transmit.A colpitts oscillator produces necessary carrier oscillations. the carrier has some amount of frequency deviation with respect to the voice or music message.

                        The voice or music is pre-amplified in the first stage,A simple colpitts oscillator doesnt give any message information,it just gives a blank carrier oscillations.we must vary its frequency in accordance with the music or voice.in order to do it,The base emitter junction of the of the colpitts oscillator is biased with the voice or music signals .the voice or music signal voltage varies the junction capacitance of the oscillator.such that the capacitance of the junction is varied with the voice or music signal voltage.this variation in the capacitance inturn varies the frequency of oscillations.

                        hence the frequency variations are produced with the variations in the voice or music signal.

                      This frequency modulated signal is now ready to be transmitted across the free space.using a proper antenna with good matching characteristics we can transmit the frequency modulated signal in to air the form of electromagnetic radiations.

                       A commercial FM receiver can catch this electromagnetic radiations and convert it to electrical signal and demodulate it back to the original voice or music signal. demodulator is a commercial receiver which uses  a phase locked loop circuitry.

                    Hence following the method described above we can thus transmit and receive a voice and music signal wirelesly over the free space.

 

 

 CONTN............READ MORE>>>>

authors:

P.SHOBHA (Btech RVR&JC COLLEGE OF ENGG.)

S.VENKATESH (Btech RVR&JC COLLEGE OF ENGG.)

T.RAGHURAM (Btech RVR&JC COLLEGE OF ENGG.)

M.KRISHNA KANTH(Btech RVR&JC COLLEGE OF ENGG.)

P.PRABHATH(Btech RVR&JC COLLEGE OF ENGG.)

I sincerely thank authors,the students of "RVR&JC COLLEGE OF ENGG"

for their great support.

my special thanks to v.v.m.m.rao 

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