This circuit allows for FM modulation in the aforementioned wireless microphone or radio. Here, a back-to-back varactor configuration minimizes the effects of RF modulation.

Building a frequency modulation circuit The FM modulator circuit (frequency modulation) is built with a Motorola MC1648P oscillator. Two ... The output level of the modulator is -5 dBm. In this fm ...

As V increases, d increases and C decreases. There’s your voltage controlled capacitor. Any diode can be used this way but most diodes are designed to minimize junction capacitance. Varactors are ...