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Spread spectrum modulating apparatus using either PSK or FSK primary modulation

  • US 5,539,770 A
  • Filed: 11/15/1994
  • Issued: 07/23/1996
  • Est. Priority Date: 11/19/1993
  • Status: Expired due to Fees
First Claim
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1. A spread spectrum modulating apparatus comprising:

  • an oscillator for generating a carrier signal;

    a frequency multiplier multiplying a frequency of the carrier signal by a predetermined integer N1;

    a frequency divider dividing the frequency of the carrier signal by a predetermined integer N2;

    a spread code generator receiving an output signal of the frequency divider as a clock signal, and generating a spread code in response to the clock signal;

    a power supply for providing a dc bias voltage;

    an operation device executing predetermined logic operation between the spread code and said dc bias voltage from said power supply;

    a switch selectively feeding an input information signal to the oscillator or combining the signal with the dc bias voltage; and

    means for multiplying an output signal of the operation device and an output signal of the frequency multiplier to execute a spectrum spreading process.

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