Simplest FM Radio, catches only 16MHz( small bandwidth of 0.1Mhz) . The AC source is an antenna.
It catches a particular frequency and then increases it and passes it throw resistors.
A speaker will catch the blue peaks simultaneously at about ultrasonic frequency. But as the frequency would shift slightly (few khz), the change in frequency would be im audible range, making a person hear a slight click. By this way info can be transfered from one place to another. The AND Gate wont allow other frequencies to pass, attenuating them as they reaches below 500mv.
