US3810024A
Expired / Lapsed
US
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Method and circuit for monitoring and detecting sweep signal failure
Assignee: Westinghouse Electric Corp
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Filing: 1972-11-20
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Granted: 1974-05-07
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Expires: 1992-11-20
Abstract
Abstract A method and sweep signal monitoring circuit for protecting scanned electron tubes, particularly high sensitivity imaging devices such as television camera tubes, from damage upon loss of a sweep voltage. A monitoring circuit monitors the sweep voltage and generates, through the use of complementary gating signals, a digital signal having a first signal level for a normal sweep voltage and a second signal level for an abnormal sweep voltage. The second signal level of the digital signal not only indicates loss of the sweep voltage but also indicates undesirable changes in the zero crossing point of the sweep voltage. The signal level of the digital signal is monitored and the detection of the second signal level may result in the inhibiting of the scanning of the tube or in any other suitable protective measures.
Inventors
- 👤 J Meacham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:42
CPC Classifications
H; H04; H04N; H04N3/00; H04N3/10; H04N3/16; H04N3/20; H02; H02H; H02H7/00; H02H7/20
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
118 words
A circuit for detecting an abnormal condition of a sweep voltage which substantially linearly varies over one active cycle from one potential to another potential through a zero potential crossover point, said circuit comprising: first means for generating complementary gating signals each substantially corresponding in duration and coinciding in time to a respective half cycle of a normal active cycle of said sweep voltage; and, second means responsive to said gating signals and said sweep voltage for monitoring the position of said sweep voltage zero crossover point and for generating a sweep voltage monitoring signal having one signal level for a desired position of said crossover point and another signal level for other positions of said crossover point.
Claim 2
Dependent Claim
118 words
A circuit for detecting an abnormal condition of a sweep voltage which substantially linearly varies over one active cycle from one potential to another potential through a zero potential crossover point, said circuit comprising: first means for generating complementary gating signals each substantially corresponding in duration and coinciding in time to a respective half cycle of a normal active cycle of said sweep voltage; and, second means responsive to said gating signals and said sweep voltage for monitoring the position of said sweep voltage zero crossover point and for generating a sweep voltage monitoring signal having one signal level for a desired position of said crossover point and another signal level for other positions of said crossover point.
Claim 3
Dependent Claim
52 words
The circuit of claim 1 wherein said first means comprises a monostable mulTivibrator having a time constant approximately equal to one-half cycle of a normal active cycle of said sweep voltage, said monostable multivibrator being triggered from its stable to its unstable state by a blanking signal synchronized with said sweep voltage.
Claim 4
Dependent Claim
85 words
The circuit of claim 1 wherein said second means comprises: means for generating first and second pulses oppositely variable in duration in relation to the condition of the sweep voltage, said first and second variable duration pulses being of substantially the same duration for a normal sweep voltage condition and differing in duration from an abnormal sweep voltage condition; and, means for gating said first and second variable duration signals in response to said first and second gating signals, respectively, to generate said monitoring signal.
Claim 5
Dependent Claim
52 words
The circuit of claim 3 wherein said first means comprises a monostable multivibrator having a time constant approximately equal to one-half cycle of a normal active cycle of said sweep voltage, said monostable multivibrator being triggered from its stable to its unstable state by a blanking signal synchronized with said sweep voltage.
Claim 6
Dependent Claim
42 words
The circuit of claim 1 wherein said second means comprises: means for inverting said sweep voltage; and, means for gating said sweep voltage and said inverted sweep voltage respectively to said first and second gating signals, respectively, to generate said monitoring signal.
Claim 7
Dependent Claim
52 words
The circuit of claim 5 wherein said first means comprises a monostable multivibrator having a time constant approximately equal to one-half cycle of a normal active cycle of said sweep voltage, said monostable multivibrator being triggered from its stable to its unstable state by a blanking signal synchronized with said sweep voltage.
Claim 8
Dependent Claim
116 words
A circuit for monitoring a sweep voltage which substantially linearly varies over one active cycle from one potential to another potential through a zero potential crossover point, said circuit comprising: means for generating first and second pulses oppositely variable in duration in response to a change in the position of the zero crossover point of said sweep voltage; means for generating first and second gating signals each substantially corresponding in duration and coinciding in time to a respective half cycle of an active normal cycle of said sweep voltage; and, means for gating first and second variable duration pulses in response to said first and second gating pulses, respectively, to provide a sweep voltage monitoring signal.
Claim 9
Dependent Claim
116 words
A circuit for monitoring a sweep voltage which substantially linearly varies over one active cycle from one potential to another potential through a zero potential crossover point, said circuit comprising: means for generating first and second pulses oppositely variable in duration in response to a change in the position of the zero crossover point of said sweep voltage; means for generating first and second gating signals each substantially corresponding in duration and coinciding in time to a respective half cycle of an active normal cycle of said sweep voltage; and, means for gating first and second variable duration pulses in response to said first and second gating pulses, respectively, to provide a sweep voltage monitoring signal.
Claim 10
Dependent Claim
46 words
The circuit of claim 7 wherein said means for generating said first and second pulses comprises first and second zero bilevel crossover detectors eah biased to change levels on opposite sides of said zero crossover point such that said first and second pulses overlap in time.
Claim 11
Dependent Claim
54 words
The circuit of claim 8 wherein said gating signal generating means comprises a monostable multivibrator having a time constant approximately equal to one-half cycle of a normal active cycle of said sweep voltage, said monostable multivibrator being triggered from its stable to its unstable state by a blanking signal synchronized with said sweep voltage.
Claim 12
Dependent Claim
139 words
A circuit for protecting a scanned electron tube against damage due to an abnormal condition of a sweep voltage which cyclically repeats at a predetermined rate comprising: means for generating first and second complementary gating signals in response to a first blanking signal; means for inverting the sweep voltage; means for gating the sweep voltage and the inverted sweep voltage responsively to said first and second gating signals, respectively, to generate a digital signal having a first signal level for a normal condition of the sweep voltage and having a second signal level for an abnormal condition of the sweep voltage; and means for periodically sampling the level of said generated digital signal at a rate exceeding the repetition rate of the sweep voltage and for generatIng a unique signal responsively to the sampling of said second signal level.
Claim 13
Dependent Claim
139 words
A circuit for protecting a scanned electron tube against damage due to an abnormal condition of a sweep voltage which cyclically repeats at a predetermined rate comprising: means for generating first and second complementary gating signals in response to a first blanking signal; means for inverting the sweep voltage; means for gating the sweep voltage and the inverted sweep voltage responsively to said first and second gating signals, respectively, to generate a digital signal having a first signal level for a normal condition of the sweep voltage and having a second signal level for an abnormal condition of the sweep voltage; and means for periodically sampling the level of said generated digital signal at a rate exceeding the repetition rate of the sweep voltage and for generatIng a unique signal responsively to the sampling of said second signal level.
Claim 14
Dependent Claim
37 words
The circuit of claim 10 wherein said sampling and unique signal generating means comprises a selectively steered bistable multivibrator clocked in response to a second blanking signal having a repetition frequency greater than said first blanking signal.
Claim 15
Dependent Claim
60 words
The circuit of claim 11 wherein said digital signal generating means comprises: means for generating first and second complementary gating signals in response to said first blanking signal; means for inverting the sweep voltage; and, means for gating the sweep voltage and the inverted sweep voltage responsively to said first and second gating signals, respectively, to generate said digital signal.
Claim 16
Independent Claim
119 words
A method for detecting an abnormal condition of a sweep voltage which substantially linearly varies over one active cycle from one potential to another potential through a zero potential crossover point, said method comprising the steps of: generating first and second complementary gating signals each substantially corresponding in duration and coinciding in time to a respective half cycle of a normal active cycle of the sweep voltage; and, monitoring the position of the sweep voltage zero crossover point and generating a sweep voltage monitoring signal having one signal level for a desired position of said crossover point and another signal level for other positions of said crossover point in response to the generated gating signals and the sweep voltage.
Claim 17
Independent Claim
119 words
A method for detecting an abnormal condition of a sweep voltage which substantially linearly varies over one active cycle from one potential to another potential through a zero potential crossover point, said method comprising the steps of: generating first and second complementary gating signals each substantially corresponding in duration and coinciding in time to a respective half cycle of a normal active cycle of the sweep voltage; and, monitoring the position of the sweep voltage zero crossover point and generating a sweep voltage monitoring signal having one signal level for a desired position of said crossover point and another signal level for other positions of said crossover point in response to the generated gating signals and the sweep voltage.
Claim 18
Dependent Claim
50 words
The circuit of claim 13 wherein the gating signals are generated by triggering a monostable multivibrator having a time constant approximately equal to one-half cycle of a normal active cycle of the sweep voltage from its stable to its unstable state with a blanking signal synchronized with the sweep voltage.
Claim 19
Dependent Claim
89 words
The method of claim 13 wherein the position of the sweep voltage zero crossover point is monitored by: generating first and second pulses oppositely variable in duration in relation to the condition of the sweep voltage, the first and second variable duration pulses being of substantially the same duration for a normal sweep voltage condition and differing in duration for an abnormal sweep voltage condition; and, gating the first and second variable duration signals in response to the first and second gating signals, respectively, to generate said monitoring signal.
Claim 20
Dependent Claim
50 words
The method of claim 15 wherein the gating signals are generated by triggering a monostable multivibrator having a time constant approximately equal to one-half cycle of a normal active cycle of the sweep voltage from its stable to its unstable state with a blanking signal synchronized with the sweep voltage.
Claim 21
Dependent Claim
46 words
The method of claim 13 wherein the position of the sweep voltage zero crossover point is monitored by: inverting the sweep voltage; and, gating the sweep voltage and the inverted sweep voltage responsively to the first and second gating signals, respectively, to generate the monitoring signal.
Claim 22
Dependent Claim
50 words
The method of claim 17 wherein the gating signals are generated by triggering a monostable multivibrator having a time constant approximately equal to one-half cycle of a normal active cycle of the sweep voltage from its stable to its unstable state with a blanking signal synchronized with the sweep voltage.
References Cited (Backward Citations)
US2868975A
Cited
US2882445A
Cited
US3302033A
Cited
US3308333A
Cited
US3439282A
Cited
US3374391A
Cited
US3458822A
Cited
US3501670A
Cited
US3588608A
Cited
US3715499A
Cited
US3714463A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-06 | 1977-11-05 | 1978-05-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-06 | 1981-11-05 | 1982-05-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-06 | 1985-11-05 | 1986-05-07 | $7700.00 | Window Closed / Lapsed |