×

Transmission system for still-picture TV telephone

  • US 5,063,587 A
  • Filed: 03/29/1990
  • Issued: 11/05/1991
  • Est. Priority Date: 03/30/1989
  • Status: Expired due to Fees
First Claim
Patent Images

1. A still-picture TV telephone system for transmitting and receiving, via a telephone circuit, a still picture taken by a camera, comprising:

  • (a) a voice band filter means for eliminating a special band signal of a voice signal introduced from a transmitting means;

    (b) a low-pass filter means for restricting a still picture signal in band, cut-off frequencies of said low-pass filter means being set to less than or equal to 1/2 of the restricted band of said voice band filter means;

    (c) a phase/amplitude modulation means for modulating the phase and amplitude of the still picture signal, high frequency components of which have been eliminated, by a carrier signal, frequencies of the carrier signal being set to substantially central frequencies of the signal-free band of said voice band filter means, a baud rate frequency being set substantially to the restricted band width of said voice band filter means; and

    (d) a composer means for composing a picture transmission signal of modulated phase and amplitude in the narrow band and a voice transmission signal of the restricted band to divide frequency bands of the picture and voice signals and, at the same time, to transmit the picture and voice signals.

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