US4881253A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mis-detection of a video switchover key signal
Assignee: Sony Corp
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Filing: 1988-06-08
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Granted: 1989-11-14
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Expires: 2008-06-08
Abstract
Abstract A television telephone system utilizes a tone signal of a predetermined duration. The tone signal has a plurality of frequencies and is positioned at the starting portion of a transmission signal. The tone signal reduces the possibility of mis-detection of signals during reception and allows video signals to be transmitted more satisfactorily.
Inventors
- 👤 Kenichi Takeuchi
- 👤 Shin Saito
- 👤 Shoji Araki
- 👤 Atsushi Nakayama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:44
CPC Classifications
H; H04; H04M; H04M11/00; H04N; H04N7/00; H04N7/14; H04N7/141; H04N7/148
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
192 words
A television telephone system comprising: (a) an image pick-up section; (b) a picture receiving display section, said image pick-up section and said picture receiving display section counted within a single housing; (c) an image pick-up control section for timebase-compressing a desired video signal from said image pick-up by said image pick-up section, transmitting through telephone lines said desired video signal to a television telephone set of the other party, processing said desired video signal and an audio signal from a terminal apparatus of said other party and reproducing the video signal on said picture receiving display section; (d) a tone signal generating means for generating a tone signal having a predetermined duration, said tone signal being formed of at least of two frequencies and positioned at least at the starting portion of said transmission video signal; (e) a detecting means for detecting said tone signal having at least two frequencies from a received transmission signal; and (f) a means for starting the reception processing of the received transmission signal when said tone signals are detected for more than a predetermined ratio of a predetermined period of time from the received transmission signal.
Claim 2
Dependent Claim
192 words
A television telephone system comprising: (a) an image pick-up section; (b) a picture receiving display section, said image pick-up section and said picture receiving display section counted within a single housing; (c) an image pick-up control section for timebase-compressing a desired video signal from said image pick-up by said image pick-up section, transmitting through telephone lines said desired video signal to a television telephone set of the other party, processing said desired video signal and an audio signal from a terminal apparatus of said other party and reproducing the video signal on said picture receiving display section; (d) a tone signal generating means for generating a tone signal having a predetermined duration, said tone signal being formed of at least of two frequencies and positioned at least at the starting portion of said transmission video signal; (e) a detecting means for detecting said tone signal having at least two frequencies from a received transmission signal; and (f) a means for starting the reception processing of the received transmission signal when said tone signals are detected for more than a predetermined ratio of a predetermined period of time from the received transmission signal.
Claim 3
Dependent Claim
28 words
A television telephone system according to claim 1, wherein said video signal includes a signal pause period of a predetermined duration which is provided after said tone signal.
Claim 4
Dependent Claim
27 words
A television telephone system according to claim 1, wherein said video signal includes a non-modulated signal having a predetermined duration which is provided after said tone signal.
Claim 5
Dependent Claim
43 words
A television telephone system as claimed in claim 1, further comprising a change-over switch means for automatically switching a telephone lines from a standard telephone to said video signal processing means when said tone signal is detected by said tone signal detecting means.
Claim 6
Dependent Claim
33 words
A television telephone system according to claim 1, wherein said tone signal detecting means produces a change-over key signal when the integrated time value of said received tone signal reaches a predetermined value.
Claim 7
Dependent Claim
20 words
A television telephone system according to claim 1 including a microcomputer forming a part of said image pickup control section.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-11-13 | 1993-05-15 | 1993-11-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-11-13 | 1997-05-15 | 1997-11-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-11-13 | 2001-05-15 | 2001-11-14 | $7700.00 | Window Closed / Lapsed |