4. Methodology of Radio Modulating signal Carrier Wave Modulated Wave Microphon e Broadcast Tower How radio electromagnetic waves are changed to Radio Waves - Radio
5. In Realty it works like this: Phase 1 : Baseband Or the Original signal message signal Phase 2 : After carrier being sent then modulating siganl
26. Front end converter The S-band signals received after LNA are down converted to the IF at 70 MHz nominal. The LO input to the mixer is 2505 MHz at 7 dBm
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28. The 52 MHz band signals coming from FTP are amplified in IF amplifier having a gain of 50 dB. Then the output is divided into three outputs using power divider . The 92 MHz band signals coming from FTP are also amplified in 50 dB. IF amplifier then converted into 52 MHz band after beating with 40 MHz oscillator. The output of mixer is passed through a band pass filter and then amplified and further divided into three outputs.
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30. Synthesizer unit This unit consists of six modules of synthesized frequency translator . Each module takes the 52 MHz IF. Synthesizer is used as a variable local oscillator. It consists of a VCO and a PLL. In PLL synthesizer a reference signal is generated using a crystal of 2.048 MHz
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33. Working Of an FM Transmitter L R Stereo coder VHF oscillator & modulator Wide Band Power Amplifier Frequency crystal oscillator 10Mhz Frequency divider 1/1000 Phase detector Rectifier and filter Programmable divider 1/N antenna
44. variable tuning capacitor (150pF) coil aerial Our tuner uses a coil of wire (called an inductor) and a capacitor. The combination of inductor and capacitor makes something called a “ resonator ”-- it is a circuit that throws away all the unwanted signals, and keeps only the one that we want . The resonator resonates at a particular frequency that is determined by the size of the inductor and capacitor. The charge sloshes back and forth in the tank circuit at a certain frequency and the station being tuned in to must be very near that frequency In my radios, I will use a capacitor that has a fixed size, and i will “tune” the radio to different stations by changing the size (the "inductance") of the inductor. Working of tuner circuit Phase 1
45. Working of tuner phase 2 The tuner coil has about 200 turns of wire with a thin red insulation on it. The insulation is scraped away on the top. To tune the radio, we will use a brass strip with a contact on the end that will make electrical contact at different points along the coil, where the insulation was scraped away . By pivoting the brass strip about a screw, the sliding contact will move across the coil, changing its inductance . When the contact is near one end the inductance will be very small , and the circuit will tune in radio stations whose carrier frequency is very high . When the contact is near the other end, the inductance will be large and the circuit will tune in radio stations whose carrier frequency is very low. pivot
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