×

Digital data over voice communication

  • US 5,025,443 A
  • Filed: 04/28/1989
  • Issued: 06/18/1991
  • Est. Priority Date: 02/24/1988
  • Status: Expired due to Fees
First Claim
Patent Images

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 in bit intervals of duration T;

    (b) coding means for forming linear combinations of said pulsed data signals with delayed and advanced version thereof to sinusoidally encode the pulses in the frequency domain by converting each data bit into a corresponding data symbol having a duration 5T/2, the data symbol being composed of five pulses spaced T/2 apart having alternately opposite polarities and equal durations of not more than T/2, the amplitudes of a first pair of pulses on either side of a central pulse being equal and being "a" times an amplitude of the central pulse, where "a" is a factor ≦

    1, and the amplitudes of a second pair of pulses on either side of the first pair of pulses being equal and being "b" times the amplitude of the central pulse where "b" is a factor ≦

    1.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×