US3916402A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Synchronization of display frames with primary power source
Assignee: International Business Machines Corp
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Filing: 1973-12-17
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Granted: 1975-10-28
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Expires: 1993-12-17
Abstract
Abstract A dynamic shift register (DSR) refresh buffer is alternately clocked at one of two rates to complete exactly one revolution per frame of a cathode ray tube (CRT) display device which displays one frame per cycle of the primary power source supplying power to the display device. The time during which data codes are read from the DSR for display on the CRT (electronic frame time) is less than the minimum period of the primary power source. Variations in the period of the primary power source are absorbed by delaying the beginning of the subsequent frame until after the beginning of the subsequent period of the primary power source is detected. A positive peak detector is connected to the 60 Hz. AC primary power source which powers the CRT display. Display of a frame is begun at a fixed time delay after the detection of the positive peak of the primary power source. Data is displayed in synchronism with the normal rate of shifting of the DSR. At the end of the electronic frame time the rate of shifting characters in the DSR is halved and a counter is incremented upwardly from zero at a fixed rate until the next positive peak of the primary power source is detected. When the next positive peak is detected, the counter is incremented downwardly until it reaches zero, at which time the shift rate of characters in the DSR is restored to the normal rate. Subsequently, the fixed time delay from the detection of the positive peak expires, and display of the next frame begins. Characters continue to be shifted in the DSR at the normal rate until the end of the next electronic frame. In this manner a frame of characters is displayed and synchronized with each cycle of the primary power source powering the CRT.
Inventors
- 👤 Louis Michael Hornung
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 23:19
CPC Classifications
G; G09; G09G; G09G5/00; G09G5/12; G09G5/22; G09G5/222
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
155 words
A system for displaying frames of characters and spaces, comprising: recirculating dynamic storage means having a number of data code storage positions for storing data codes corresponding to data displayed in one of said frames and an additional number of storage positions; display means connected to said storage means for displaying said frame, said display means being operative in response to a periodic waveform; means for measuring the elapsed time, Tm, between the shifting of said data codes out of the last data code storage position of said frame and the occurrence of a particular characteristic of said waveform and; control means for selectively shifting said data codes in said storage means through said additional number of storage positions at more than one rate during the time between frames, said control means including means for prorating the shifting of data codes amonG said more than one rate as a function of said elapsed time, Tm.
Claim 2
Independent Claim
155 words
A system for displaying frames of characters and spaces, comprising: recirculating dynamic storage means having a number of data code storage positions for storing data codes corresponding to data displayed in one of said frames and an additional number of storage positions; display means connected to said storage means for displaying said frame, said display means being operative in response to a periodic waveform; means for measuring the elapsed time, Tm, between the shifting of said data codes out of the last data code storage position of said frame and the occurrence of a particular characteristic of said waveform and; control means for selectively shifting said data codes in said storage means through said additional number of storage positions at more than one rate during the time between frames, said control means including means for prorating the shifting of data codes amonG said more than one rate as a function of said elapsed time, Tm.
Claim 3
Dependent Claim
33 words
The system of claim 1 wherein said control means further comprises means for shifting said data codes more than one storage position after each occurrence of said particular characteristic of said periodic waveform.
Claim 4
Dependent Claim
52 words
The system of claim 2 wherein said control means further comprises: oscillator means for generating storage means shifting pulses at a first rate; and division means for generating storage means shifting pulses at a second rate different from said first rate, said division means having an input connected to said oscillator means.
Claim 5
Dependent Claim
12 words
The system of claim 3 wherein said waveform is a sinusoidal waveform.
Claim 6
Dependent Claim
22 words
The system of claim 4 wherein said means for measuring said Tm further comprises a sensing means including a peak detector circuit.
Claim 7
Dependent Claim
14 words
The system of claim 5 wherein said storage means includes a dynamic shift register.
Claim 8
Dependent Claim
14 words
The system of claim 6 wherein said display means includes a cathode ray tube.
Claim 9
Dependent Claim
31 words
The system of claim 3 wherein said division means includes a divide-by-two circuit having an input connected to said oscillator means, whereby said second rate is one-half of said first rate.
Claim 10
Dependent Claim
110 words
The system of claim 8 wherein said control means includes a bi-directional counter, said counter being incremented from an initial count in a first direction at a fixed rate during the time between the shifting of said data codes out of the last data code storage position of said one of said frames and said occurrence of said characteristic of said waveform, said counter being incremented in an opposite direction at said fixed rate immediately subsequent to said occurrence of said characteristic until said initial count is reached, and said division means being connected to said storage means while said counter has a count therein other than said initial count.
Claim 11
Independent Claim
153 words
A method of synchronizing the display of frames of characters and spaces with a periodic waveform by which a display device is energized, comprising: storing data codes corresponding to one of said frames to be displayed in a recirculating dynamic shift register having a number of storage positions for storing said data codes and an additional number of storage positions; measuring the elapsed time, Tm, between the shifting of said data codes out of the last data code storage position of said frame and the occurrence of a particular characteristic of said waveform; shifting, in response to said shifting of said data codes out of said last data code storage position of one of said frames, said data codes through said additional number of storage positions at more than one rate during the time between frames, including; prorating the shifting rates of said data codes as a function of said elapsed time, Tm.
Claim 12
Independent Claim
153 words
A method of synchronizing the display of frames of characters and spaces with a periodic waveform by which a display device is energized, comprising: storing data codes corresponding to one of said frames to be displayed in a recirculating dynamic shift register having a number of storage positions for storing said data codes and an additional number of storage positions; measuring the elapsed time, Tm, between the shifting of said data codes out of the last data code storage position of said frame and the occurrence of a particular characteristic of said waveform; shifting, in response to said shifting of said data codes out of said last data code storage position of one of said frames, said data codes through said additional number of storage positions at more than one rate during the time between frames, including; prorating the shifting rates of said data codes as a function of said elapsed time, Tm.
Claim 13
Dependent Claim
39 words
The method of claim 10 wherein said step of shifting said data codes through said additional number of storage positions further comprises shifting said codes more than one position after said occurrence of said particular characteristic of said waveform.
Claim 14
Dependent Claim
131 words
The method of claim 11 wherein said step of shifting said data codes through said additional number of storage positions at more than one rate further comprises: incrementing a counter from an initial count in a first direction at a fixed rate during the time between said shifting of said data codes out of said last data code storage position of said frame and said occurrence of said particular characteristic of said waveform; incrementing said counter in an opposite direction at said fixed rate immediately subsequent to said occurrence of said characteristic of said waveform until said initial count is reached; and shifting said data codes in said storage means at a slower of said more than one rate while said counter has a count therein other than said initial count.
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) | 1978-10-27 | 1979-04-28 | 1979-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-27 | 1983-04-28 | 1983-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-27 | 1987-04-28 | 1987-10-28 | $7700.00 | Window Closed / Lapsed |