US4542406A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Video/audio simultaneous transmission system
Assignee: Fujitsu Ltd
•
Filing: 1982-12-07
•
Granted: 1985-09-17
•
Expires: 2002-12-07
Abstract
Abstract The horizontal sync signal contained in the video signal from a video apparatus sometimes undergoes phase jump, resulting in failure of multiplexing of audio and video signals based on the horizontal sync signal. A sync signal switching circuit is adapted to produce a modified sync signal by switching the sync signal to a local sync signal upon occurrence of the phase jump, thereby assuring the multiplexing of audio and video signals.
Inventors
- 👤 Haruo Shimoyama
- 👤 Toshio Ohshima
- 👤 Shinobu Nomoto
- 👤 Makoto Hiraoka
- 👤 Toshio Hanabata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:11
CPC Classifications
H; H04; H04N; H04N21/00; H04N21/20; H04N21/23; H04N21/236; H04N21/2368; H04N21/23602; H04N21/242; H04N21/40; H04N21/43; H04N21/4302; H04N21/4305; H04N21/434; H04N21/4341; H04N21/4342; H04N7/00; H04N7/24; H04N7/52; H04N7/54; H04N7/56
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
140 words
A video/audio simultaneous transmission system comprising: means for sampling and encoding a video signal inclusive of horizontal sync signals occurring at indefinite time intervals in response to a first clock signal having a recurrence period independent of the recurrence period of the horizontal sync signal; means for sampling and encoding an audio signal in response to a second clock signal having a predetermined recurrence period; means for generating a sync signal in response to the horizontal sync signal; means for modifying the sync signal to produce a modified sync signal on the basis of said first clock signal; and means responsive to a third clock signal each time it receives the modified sync signal, for transmitting a special code different from the codes of the encoded audio and video signal data and thereafter the encoded audio and video signals successively.
Claim 2
Dependent Claim
140 words
A video/audio simultaneous transmission system comprising: means for sampling and encoding a video signal inclusive of horizontal sync signals occurring at indefinite time intervals in response to a first clock signal having a recurrence period independent of the recurrence period of the horizontal sync signal; means for sampling and encoding an audio signal in response to a second clock signal having a predetermined recurrence period; means for generating a sync signal in response to the horizontal sync signal; means for modifying the sync signal to produce a modified sync signal on the basis of said first clock signal; and means responsive to a third clock signal each time it receives the modified sync signal, for transmitting a special code different from the codes of the encoded audio and video signal data and thereafter the encoded audio and video signals successively.
Claim 3
Dependent Claim
128 words
A video/audio simultaneous transmission system according to claim 1 wherein said modifying means comprises: means for inhibiting insertion of a sync signal in the modified sync signal when the sync signal occurs before a first instant following lapse of a first predetermined period of time from an instant of occurrence of an immediately preceding sync signal; means for permitting insertion of a sync signal in the modified sync signal when the sync signal occurs before a second instant following lapse of a second predetermined period of time from the first instant; and means for permitting insertion of a local sync signal in the modified sync signal at the second instant when the sync signal does not occur during the period between the first instant and the second instant.
Claim 4
Dependent Claim
98 words
A video/audio simultaneous transmission system according to claim 2 comprising: signal generating means counting said first clock, for generating a time window signal and the local sync signal, said time window signal defining the first predetermined period of time; signal switching means for switching the sync signal and the local sync signal to provide the modified sync signal, said modified sync signal being returned to said signal generating means to reset the same; and means responsive to the sync signal, the local sync signal and the time window signal, for controlling the switching of said signal switching means.
References Cited (Backward Citations)
US3755624A
Cited
JPS5731277A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-09-16 | 1989-03-18 | 1989-09-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-16 | 1993-03-18 | 1993-09-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-16 | 1997-03-18 | 1997-09-17 | $7700.00 | Window Closed / Lapsed |