Patent ID: 6246864
Filing Date: 2001-06-12
Classification: H04B

Abstract:
A wireless microphone use UHF band carrier FM transmitter adopting a PLL circuit that includes an analog phase comparator, and a loop filter connected to the output of said phase comparator, said transmitter comprising:a crystal oscillation circuit for generating an oscillation signal; anda voltage controlled crystal oscillation type modulation circuit having an input for receiving a modulation signal with a frequency of an acoustic signal, for FM modulating said oscillation signal generated by said crystal oscillation circuit by said modulation signal to generate an FM modulated signal;said analog phase comparator having a reference input for receiving a reference signal, said reference signal being said FM modulated signal obtained from the voltage controlled crystal oscillation type modulator;said loop filter having a high band side cutoff frequency that is equal to or greater than .degree.KHz.