US3584235A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Video defect eliminator
Assignee: AT&T Inc
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Filing: 1968-10-18
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Granted: 1971-06-08
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Expires: 1988-10-18
Abstract
Abstract The specification describes a circuit for eliminating spurious voltage transients from video signals, typically arising from defects in the target of the camera tube. It comprises a twotransistor gate in combination with a delay network in one channel so that the transients reach the gate transistors at slightly different times. The unwanted pulse is blocked by the gate. Selective gain is used to narrow the pulse width of the high frequency defects so that a greater number of defects will fall within a given delay period.
Inventors
- 👤 Hatsuaki Fukui
- 👤 William J Mcnamara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 21:55
CPC Classifications
H; H04; H04N; H04N3/00; H04N3/10; H04N3/16
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
158 words
A defect eliminator for removing spurious voltage transients from a video signal comprising a transistor gate circuit comprising two matched transistors connected in parallel, means for biasing the collector of each transistor with A common voltage so as to operate the transistors in a common collector or emitter follower configuration, a delay network connected in series with the base of one transistor, input means adapted for connecting a video signal generator as the base input of the transistor gate circuit, output means adapted for connecting a video receiver to the emitter output of the gate circuit, and a selective gain circuit interposed between the video signal generator and the transistor gate the selective gain circuit providing the approximate function: G 1+k(f/fo)x where G is gain, k is the circuit constant and has a value between 0.6 and 1.5, f is the instantaneous signal frequency, fo is an arbitrary reference frequency, and x has a value greater than 1.
Claim 2
Dependent Claim
158 words
A defect eliminator for removing spurious voltage transients from a video signal comprising a transistor gate circuit comprising two matched transistors connected in parallel, means for biasing the collector of each transistor with A common voltage so as to operate the transistors in a common collector or emitter follower configuration, a delay network connected in series with the base of one transistor, input means adapted for connecting a video signal generator as the base input of the transistor gate circuit, output means adapted for connecting a video receiver to the emitter output of the gate circuit, and a selective gain circuit interposed between the video signal generator and the transistor gate the selective gain circuit providing the approximate function: G 1+k(f/fo)x where G is gain, k is the circuit constant and has a value between 0.6 and 1.5, f is the instantaneous signal frequency, fo is an arbitrary reference frequency, and x has a value greater than 1.
Claim 3
Dependent Claim
34 words
The defect eliminator of claim 1 wherein the selective gain is obtained with a dual channel amplifier comprising a straight channel, a two-stage differentiating channel and a differential amplifier for combining the two channels.
Claim 4
Dependent Claim
14 words
The defect eliminator of claim 2 further including an amplifier following each differentiating stage.
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) | 1974-06-07 | 1974-12-07 | 1975-06-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-07 | 1978-12-07 | 1979-06-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-07 | 1982-12-07 | 1983-06-08 | $7700.00 | Window Closed / Lapsed |