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Wireless microphone use UHF band carrier FM transmitter

  • US 6,246,864 B1
  • Filed: 09/23/1998
  • Issued: 06/12/2001
  • Est. Priority Date: 09/25/1997
  • Status: Expired due to Fees
First Claim
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1. 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; and

    a 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 °

    KHz.

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