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Superheterodyne tranceiver with bilateral first mixer and dual phase locked loop frequency control

  • US 5,423,076 A
  • Filed: 09/24/1993
  • Issued: 06/06/1995
  • Est. Priority Date: 09/24/1993
  • Status: Expired due to Fees
First Claim
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1. A transceiver operable in alternate receive and transmit modes, which comprises:

  • a first conversion stage including a first mixer having an input terminal, an output terminal and an injection terminal, means for coupling the input terminal of the first mixer to antenna means for receiving and transmitting radio frequency signals, first means for generating frequency signals, first means for generating frequency signals at a numerically controlled frequency of a first range of frequencies coupled to the injection terminal of the first mixer for applying to the injection terminal of the first mixer an injection signal at a frequency for a frequency up-conversion during periods of operation of the transceiver in a transmit mode, and at a frequency for a frequency down-conversion during periods of operation of the transceiver in a receiver mode; and

    a second conversion stage selectively coupled with said first conversion stage including a second mixer having an input terminal, an output terminal and an injection terminal, second means for generating frequency signals at a numerically controlled frequency of a second range of frequencies, frequency ratio circuit means for providing in response to a voltage controlled oscillator signal first and second frequency output signals at a two-to-one ratio, respectively, means for coupling a generated frequency signal from the second frequency generator to the frequency ratio circuit means, means for coupling the first frequency output signal to the output signal to the output terminal of the first mixer upon the transceiver being operable in the transmit mode and for coupling the second frequency output signal to the injection terminal of the second stage upon the transceiver being operable in the receive mode.

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