US3781477A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Picture telephone system at which the video signal is adapted to the character of the picture
Assignee: Telefonaktiebolaget LM Ericsson AB
•
Filing: 1971-05-17
•
Granted: 1973-12-25
•
Expires: 1991-05-17
Abstract
Abstract In a picture telephone system means are included at both ends of a telephone connection between two subscribers for adjusting the frame rate of pictures so that with a limited channel band width good resolution is obtained both for stationary detailed pictures such as documents and for moving pictures requiring less resolution such as conversing subscribers.
Inventors
- 👤 N Johnannesson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 06:02
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/14; H04N7/141; H04N7/147
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
304 words
In a picture telephone system having a plurality of picture telephone apparatuses each having a picture transmitting and receiving part and a voice transmitting and receiving part, and interconnected telephone exchanges having switching means for connecting the picture transmitting-receiving part of a calling subscriber to the corresponding part of a called subscriber via a video signal line and switching means for connecting the voice transmitting and receiving part of a calling subscriber to the corresponding part of a called subscriber through a voice signal line, apparatus for controlling the frame rate of video transmission between a calling subscriber and a called subscriber comprising at least two video signal adjustment means, one associated with the calling subscriber, the other associated With the called subscriber, each of said video signal adjustment means including first frame rate adjusting means for adjusting the frame rate of the picture to be transmitted and second frame rate adjusting means for adjusting the frame rate of the picture to be received, each of the picture telephone apparatuses including means for generating a first control signal for indicating the frame rate desired by the subscriber, at least two transmission equipment means, one associated with the calling subscriber, the other associated with the called subscriber, each of said transmission equipment means including control means for controlling the frame rate adjusting means of its associated video signal adjustment means and including transmitting means for transmitting a second control signal to the other transmission equipment means, the control means and transmitting means of each of said transmitting equipment means operating in response to either a first control signal from the associated picture telephone apparatus or a second control signal from the other transmitting equipment means whereby either the calling or the called subscriber can select the frame rate for the video communication between the subscribers.
Claim 2
Dependent Claim
304 words
In a picture telephone system having a plurality of picture telephone apparatuses each having a picture transmitting and receiving part and a voice transmitting and receiving part, and interconnected telephone exchanges having switching means for connecting the picture transmitting-receiving part of a calling subscriber to the corresponding part of a called subscriber via a video signal line and switching means for connecting the voice transmitting and receiving part of a calling subscriber to the corresponding part of a called subscriber through a voice signal line, apparatus for controlling the frame rate of video transmission between a calling subscriber and a called subscriber comprising at least two video signal adjustment means, one associated with the calling subscriber, the other associated With the called subscriber, each of said video signal adjustment means including first frame rate adjusting means for adjusting the frame rate of the picture to be transmitted and second frame rate adjusting means for adjusting the frame rate of the picture to be received, each of the picture telephone apparatuses including means for generating a first control signal for indicating the frame rate desired by the subscriber, at least two transmission equipment means, one associated with the calling subscriber, the other associated with the called subscriber, each of said transmission equipment means including control means for controlling the frame rate adjusting means of its associated video signal adjustment means and including transmitting means for transmitting a second control signal to the other transmission equipment means, the control means and transmitting means of each of said transmitting equipment means operating in response to either a first control signal from the associated picture telephone apparatus or a second control signal from the other transmitting equipment means whereby either the calling or the called subscriber can select the frame rate for the video communication between the subscribers.
Claim 3
Dependent Claim
14 words
The apparatus of claim 1 wherein said frame rate adjusting means are scan converters.
Claim 4
Dependent Claim
16 words
The system of claim 1 wherein said video signal adjustment means are in the telephone exchanges.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-24 | 1977-06-25 | 1977-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-24 | 1981-06-25 | 1981-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-24 | 1985-06-25 | 1985-12-25 | $7700.00 | Window Closed / Lapsed |