US4805022A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital wipe generator
Assignee: Grass Valley USA LLC
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Filing: 1988-02-19
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Granted: 1989-02-14
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Expires: 2008-02-19
Abstract
Abstract A digital wipe generator has a digital waveform generator to generate X and Y digital waveforms from a composite sync signal. A digital wipe solid generator processes the X and Y digital waveforms to produce a digital wipe solid waveform. The wipe solid generator has a circle generator using a square root function which preshifts the sum of the squares prior to access to a look-up table, and then post shifts the output of the look-up table by one-half the amount of the preshift to produce a desired curve pattern for the digital wipe solid waveform. The digital wipe solid waveform is input to mixer circuits where it is processed to produce an anti-aliased key signal for mixing external video signals, the anti-aliasing being based upon an interpolation/decimation scheme using fractional bits of the digital wipe solid waveform. The output of the mixer circuits is a desired wipe transition.
Inventors
- 👤 John Abt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:57
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/222; H04N5/262; H04N5/265
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
85 words
A digital wipe generator comprising: means for generating from timing signals digital waveforms; means for performing arithmetical operations on the digital waveforms; means for generating a desired curve pattern from the digital waveforms; means for matrixing and combining the digital waveforms with the outputs of the performing means and the desired curve pattern generating means to produce a digital wipe solid waveform representing a desired wipe pattern; and means for combining the digital wipe solid waveform with external signals to produce a desired wipe transition.
Claim 2
Dependent Claim
85 words
A digital wipe generator comprising: means for generating from timing signals digital waveforms; means for performing arithmetical operations on the digital waveforms; means for generating a desired curve pattern from the digital waveforms; means for matrixing and combining the digital waveforms with the outputs of the performing means and the desired curve pattern generating means to produce a digital wipe solid waveform representing a desired wipe pattern; and means for combining the digital wipe solid waveform with external signals to produce a desired wipe transition.
Claim 3
Dependent Claim
95 words
A digital wipe generator as recited in claim 1 wherein the desired curve pattern generating means comprises: means for calculating an intermediate output representing the sum of the squares of the digital waveforms; means for normalizing the intermediate output to obtain an addressed pointer which uses only a predetermined number of the most significant bits after leading zeros of the intermediate output; means for producing a square root output representing the square root of the intermediate output using the address pointer; and means for shifting the square root output to produce the desired curve pattern.
Claim 4
Dependent Claim
62 words
A digital wipe generator as recited in claim 1 wherein the combining means comprises: means for splitting and modulating the digital wipe solid waveform to produce a split waveform signal; means for clipping and amplifying the split waveform signal to produce an anti-aliased key signal; and means for mixing external signals with the anti-aliased key signal to produce the desired wipe transition.
Claim 5
Dependent Claim
47 words
A digital wipe generator as recited in claim 3 wherein the combining means further comprises means for filtering the anti-aliased key signal from the clipping an amplifying means to produce a filtered anti-aliased key signal for input to the mixing means to produce the desired wipe transition.
Claim 6
Dependent Claim
47 words
A digital wipe generator as recited in claim 3 wherein the clipping and amplifying means comprises: means for interpolating the split waveform signal by using fractional bits of the split waveform signal; and means for decimating the interpolated split waveform signal to produce the anti-aliased key signal.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-02-14 | 1992-08-15 | 1993-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-14 | 1996-08-15 | 1997-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-14 | 2000-08-15 | 2001-02-14 | $7700.00 | Window Closed / Lapsed |