The RF oscillator using the inverter N2 and 10.7Mhz ceramic filter is
driving the parallel combination of N4 to N6 through N3.Since these
inverters are in parallel the output impedance will be low so that it
can directly drive an aerial of 1/4th wavelength. Since the output of
N4-N6 is square wave there will be a lot of harmonics in it. The 9th
harmonics of 10.7Mhz (96.3Mhz) will hence be at the center of the FM
band .
N1 is working as an audio amplifier. The audio signals from the microphone are amplified and fed to the varycap diode. The signal varies the capacitance of the varycap and hence varies the oscillator frequency which produce Frequency Modulation.
N1 is working as an audio amplifier. The audio signals from the microphone are amplified and fed to the varycap diode. The signal varies the capacitance of the varycap and hence varies the oscillator frequency which produce Frequency Modulation.
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