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High-speed point-to-point modem-less microwave radio frequency link using direct frequency modulation

  • US 6,823,178 B2
  • Filed: 02/14/2001
  • Issued: 11/23/2004
  • Est. Priority Date: 02/14/2001
  • Status: Expired due to Fees
First Claim
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1. An apparatus comprising:

  • a transport to microwave radio frequency adapter that accepts an input telecommunications transport signal on an input port and converts information in such signal to a desired microwave Radio Frequency (RD carrier, the input transport signal carrying information at an input bit rate, wherein the transport to microwave RF adapter further comprises;

    a voltage-control oscillator, coupled to receive the input transport signal, the voltage-control oscillator implementing a continuous phase frequency shift keyed deviation such that a first frequency is selected to indicate a first logical value for an input data bit in the transport signal and a second frequency is selected to indicate a second logical value for an input data bit in the transport signal, the deviation between the two frequencies selected to be equal to a predetermined fraction of the input bit rate;

    a first frequency multiplier connected to receive the output of the voltage-controlled oscillator and to multiply the output of the voltage controlled oscillator to the desired microwave RF carrier; and

    a microwave RF to transport adapter, to convert a received microwave RF signal to a transport signal carrying an output telecommunications transport signal, wherein the microwave RF to transport adapter further comprises;

    an oscillator, operating at a carrier frequency which is a predetermined fraction of a desired direct down-conversion frequency;

    a second frequency multiplier, connected to receive the oscillator output, and to multiply the oscillator output up to the desired direct down-conversion frequency; and

    a mixer, coupled to the frequency multiplier and the microwave RF signal, to provide a down-converted transport signal; and

    a pair of bandpass filters, a first bandpass filter tuned to a frequency which is equal to the down-conversion frequency plus one-half a data rate of the down-converted transport signal, and a second bandpass filter tuned to a frequency which is equal to the down-conversion frequency minus one-half the data rate of the down-converted transport signal.

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