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Digital data over voice communication

  • US 4,953,160 A
  • Filed: 02/24/1988
  • Issued: 08/28/1990
  • Est. Priority Date: 02/24/1988
  • Status: Expired due to Fees
First Claim
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1. Apparatus for encoding data signals for transmission at a predetermined rate over telephone lines in the presence of voice band telephone signals such that the frequency spectrum of the data signals is substantially removed from the voice band and is shifted to a higher frequency spectrum comprising:

  • (a) generator means for generating pulsed data signals;

    (b) coding means for shifting the frequency spectrum of the data signals to produce encoded data signals by forming linear combinations of said pulsed data signals with delayed and advanced versions thereof to encode the pulses in the frequency domain in the form sinm θ

    wherein θ



    fT/4; and

    wherein m is an integer greater than or equal to 1, f is a frequency variable and T is the reciprocal of the rate of the data being transmitted.

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