Facsimile and static presentation processing – Static presentation processing – Attribute control
Patent
1974-09-30
1977-02-08
Safourek, Benedict V.
Facsimile and static presentation processing
Static presentation processing
Attribute control
179 2TV, 358148, 358149, H04N 504
Patent
active
040073289
ABSTRACT:
The outlying stations of a videotelephone system, adapted to communicate with one another through a central office, include each a video-reception section and a video-transmission section as well as an audio section provided with telephone equipment. A sync-pulse generator in the video-transmission section, comprising a crystal-controlled oscillator working into a pair of frequency dividers, controls the line-scan and frame-scan generators thereof as well as those of a remote station to which it is connected via an outgoing video line. A local sync-pulse extractor connected to an incoming video line controls the line-scan and frame-scan generators of the associated video-reception section. A switch enables replacement of the crystal-controlled oscillator with a variable-frequency oscillator locked in step with the sync-pulse generator of the remote station by the output of the local sync-pulse extractor whereby interference phenomena due to pick-up of incoming sync pulses, in random phase relationship with the locally generated sync pulses, are eliminated. The switchover to the variable-frequency oscillator may be carried out manually or, at a called station, by a detector circuit responsive to incoming audio or video signals, preferably to ringing current; the detector circuit includes a relay which locks for the duration of the established connection under the control of a hook switch.
REFERENCES:
patent: 2206654 (1940-07-01), Zworykin
patent: 2757279 (1956-07-01), Vosburgh
patent: 3263027 (1966-07-01), Beltrami
patent: 3311702 (1967-03-01), Legler
patent: 3723653 (1973-03-01), Tatsuzawa
patent: 3873771 (1975-03-01), Kleinerman et al.
Chin Tommy P.
Dubno Herbert
Ross Karl F.
Safourek Benedict V.
Societa Italiana Telecomunicazioni Siemens S.p.A.
LandOfFree
Videotelephone system with anti-crosstalk means does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Videotelephone system with anti-crosstalk means, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Videotelephone system with anti-crosstalk means will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1214224