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US4760448A
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Method of measuring amplitude variations of a video carrier and apparatus therefor
Assignee: Sencore Inc
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Filing: 1987-05-04
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Granted: 1988-07-26
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Expires: 2007-05-04
Abstract
Abstract A composite RF television signal is converted to an IF signal, passed through an AGC circuit and the amplitudes of the horizontal sync pulses are sampled only during the horizontal sync period. The high and low peak samples are stored and the difference between the levels of these peak samples, which is proportional to the HUM in the system, drives a meter calibrated to show the percent of HUM in the composite RF television signals.
Inventors
- 👤 Glen Wittrock
- 👤 Barry A. Arneson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 02:38
CPC Classifications
H; H04; H04N; H04N17/00
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
79 words
A method of measuring periodic amplitude variations of a video carrier modulated with a video signal including video information and horizontal and vertical sync pulses, comprising the steps of detecting said video signal, sampling the level of said detected video signal only during the occurrence of said horizontal sync pulses, storing the maximum and minimum levels of the sampled levels occurring during a predetermined period, and displaying a visual indication of the difference between said maximum and minimum levels.
Claim 2
Independent Claim
79 words
A method of measuring periodic amplitude variations of a video carrier modulated with a video signal including video information and horizontal and vertical sync pulses, comprising the steps of detecting said video signal, sampling the level of said detected video signal only during the occurrence of said horizontal sync pulses, storing the maximum and minimum levels of the sampled levels occurring during a predetermined period, and displaying a visual indication of the difference between said maximum and minimum levels.
Claim 3
Dependent Claim
27 words
A method according to claim 1 comprising the additional step of passing said modulated video carrier through an automatic gain control circuit before detecting said video signal.
Claim 4
Independent Claim
136 words
A method of measuring periodic amplitude variations of a video carrier modulated with a video signal including video information and horizontal and vertical sync pulses, comprising the steps of detecting said video signal, separating said horizontal and vertical sync signals from the detected video signal, generating a train of sampling pulses in synchronization with and at the frequency of said horizontal sync pulses, coupling said train of sampling pulses to a sample and hold circuit to which said detected video signal is applied, interrupting said train of sampling pulses during the vertical sync period thereby to prevent sampling of said detected video signal during the vertical sync period, storing the maximum and minimum levels of said sampling pulses during a predetermined period, and displaying a visual indication of the difference between said maximum and minimum levels.
Claim 5
Independent Claim
136 words
A method of measuring periodic amplitude variations of a video carrier modulated with a video signal including video information and horizontal and vertical sync pulses, comprising the steps of detecting said video signal, separating said horizontal and vertical sync signals from the detected video signal, generating a train of sampling pulses in synchronization with and at the frequency of said horizontal sync pulses, coupling said train of sampling pulses to a sample and hold circuit to which said detected video signal is applied, interrupting said train of sampling pulses during the vertical sync period thereby to prevent sampling of said detected video signal during the vertical sync period, storing the maximum and minimum levels of said sampling pulses during a predetermined period, and displaying a visual indication of the difference between said maximum and minimum levels.
Claim 6
Independent Claim
148 words
A method of measuring periodic amplitude variations of a video carrier modulated with a video signal including video information and horizontal and vertical sync pulses, comprising the steps of passing said modulated video carrier through an automatic gain control circuit, detecting said video signal, separating said horizontal and vertical sync signals from the detected video signal, generating a train of sampling pulses in synchronization with and at the frequency of said horizontal sync pulses, coupling said train of sampling pulses to a sample and hold circuit to which said detected video signal is applied, interrupting said train of sampling pulses during the vertical sync period thereby to prevent sampling of said detected video signal during the vertical sync period, storing the maximum and minimum levels of the sampled pulses occurring during a predetermined period, and displaying a visual indication of the difference between said maximum and minimum levels.
Claim 7
Independent Claim
148 words
A method of measuring periodic amplitude variations of a video carrier modulated with a video signal including video information and horizontal and vertical sync pulses, comprising the steps of passing said modulated video carrier through an automatic gain control circuit, detecting said video signal, separating said horizontal and vertical sync signals from the detected video signal, generating a train of sampling pulses in synchronization with and at the frequency of said horizontal sync pulses, coupling said train of sampling pulses to a sample and hold circuit to which said detected video signal is applied, interrupting said train of sampling pulses during the vertical sync period thereby to prevent sampling of said detected video signal during the vertical sync period, storing the maximum and minimum levels of the sampled pulses occurring during a predetermined period, and displaying a visual indication of the difference between said maximum and minimum levels.
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) | 1991-07-26 | 1992-01-25 | 1992-07-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-07-26 | 1996-01-25 | 1996-07-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-07-26 | 2000-01-25 | 2000-07-26 | $7700.00 | Window Closed / Lapsed |