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Broadband frequency synthesizer

  • US 6,163,684 A
  • Filed: 08/01/1997
  • Issued: 12/19/2000
  • Est. Priority Date: 08/01/1997
  • Status: Expired due to Term
First Claim
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1. A tuner for receiving RF signals, said tuner comprising:

  • an input filter receiving an RF signal having a plurality of channels and removing frequencies in said RF signal above an input cutoff frequency;

    a first mixer having a first input coupled to said input filter and a second input coupled to a first reference signal, wherein said first mixer generates a first IF signal;

    a first IF filter coupled to said first mixer and filtering said first IF signal;

    a second mixer having a first input coupled to said first IF filter and a second input coupled to a second reference signal, wherein said second mixer generates a second IF signal;

    a coherent reference phase lock loop fed by said second IF signal for generating a third reference signal; and

    a frequency synthesizer comprising wide band phase locked loops (PLLs) for generating said first and second reference signals, said frequency synthesizer having a phase noise characteristic that allows said coherent reference phase lock loop to have a narrow loop bandwidth.

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