US5528307A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Clock generator
Assignee: Canon Inc
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Filing: 1995-02-27
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Granted: 1996-06-18
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Expires: 2015-02-27
Abstract
Abstract An apparatus for correcting a time base of a video signal generates a clock which is phase-synchronized with a sync. signal of the video signal and has the same frequency. In a special reproducing mode, the apparatus switches an output level of a phase comparator, which phase-compares the sync. signal and the clock to a predetermined level, which is applied to a controlled oscillator and resets a frequency divider which frequency-divides the output of the controlled oscillator, in accordance with the sync. signal to produce the video signal which can be visually recognized even in the special reproducing mode. The apparatus samples and holds the output level of the phase comparator when the video signal drops out and resets the frequency divider which produces the clock by frequency-dividing the output of the controlled oscillator, when the dropout is recovered so that a video signal of high quality is produced immediately after the recovery of the dropout of the video signal.
Inventors
- 👤 Mitsuru Owada
- 👤 Shinichi Yamashita
- 👤 Makoto Gohda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:56
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/79; H04N9/87; H04N9/89; H04N9/896
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
196 words
A time base correction apparatus comprising: (a) input means for inputting a video signal having a vertical sync. signal and other sync. signal; (b) separating means for separating the other sync. signal from the video signal; (c) phase-synchronizing means for generating a first clock synchronized with the other sync. signal and having the same frequency as the other sync. signal; said phase-synchronizing means including phase-comparing means for comparing phases of the other sync. signal and the first clock and oscillating means having an oscillation frequency thereof controlled in accordance with an output of said phase-comparing means, said first clock being generated by using a second clock generated by said oscillating means; (d) first control means for maintaining a control input to said oscillating means at a constant level according to a dropout of the video signal; (e) second control means for synchronizing the first clock to the other sync. signal after the recovery of the dropout of the video signal, said first and second control means operating to regulate said phase-synchronizing means irrespective of the vertical sync. signal; and (f) correcting means for correcting a time base of the video signal by using the second clock.
Claim 2
Dependent Claim
196 words
A time base correction apparatus comprising: (a) input means for inputting a video signal having a vertical sync. signal and other sync. signal; (b) separating means for separating the other sync. signal from the video signal; (c) phase-synchronizing means for generating a first clock synchronized with the other sync. signal and having the same frequency as the other sync. signal; said phase-synchronizing means including phase-comparing means for comparing phases of the other sync. signal and the first clock and oscillating means having an oscillation frequency thereof controlled in accordance with an output of said phase-comparing means, said first clock being generated by using a second clock generated by said oscillating means; (d) first control means for maintaining a control input to said oscillating means at a constant level according to a dropout of the video signal; (e) second control means for synchronizing the first clock to the other sync. signal after the recovery of the dropout of the video signal, said first and second control means operating to regulate said phase-synchronizing means irrespective of the vertical sync. signal; and (f) correcting means for correcting a time base of the video signal by using the second clock.
Claim 3
Dependent Claim
41 words
A time base correction apparatus according to claim 1, wherein said separating means separates a horizontal sync. signal in the video signal and the first clock has the same frequency as that of the horizontal sync. signal of the video signal.
Claim 4
Dependent Claim
50 words
A time base correction apparatus according to claim 1, wherein said phase-synchronizing means includes frequency-dividing means for frequency-dividing the second clock to generate the first clock, and said second control means resets said frequency-dividing means by the separated sync. signal in accordance with the operation of said first control means.
Claim 5
Dependent Claim
69 words
A time base correction apparatus according to claim 1, wherein said correcting means includes an AD converter for converting the video signal to a digital signal by using a variable frequency clock generated by using the second clock, and a memory for storing the output of said AD converter in accordance with the variable frequency clock and reading it out in accordance with a clock of a predetermined frequency.
Claim 6
Dependent Claim
28 words
A time base correction apparatus according to claim 4, wherein said correcting means includes a frequency multiplier for frequency-multiplying the second clock to generate the variable frequency clock.
Claim 7
Dependent Claim
58 words
A time base correction apparatus according to claim 4, wherein said video signal includes a burst signal having a higher frequency than that of the other sync. signal, and said correcting means includes phase shifting means for shifting a phase of the second clock in accordance with a phase difference between the burst signal and the second clock.
Claim 8
Dependent Claim
29 words
A time base correction apparatus according to claim 1, wherein said first control means includes sample and hold means for sampling and holding the output of said phase-comparing means.
Claim 9
Dependent Claim
41 words
A time base correction apparatus according to claim 7, wherein said first control means includes detecting means for detecting a dropout of the video signal, and said sample and hold means operates in accordance with an output of said detecting means.
Claim 10
Dependent Claim
118 words
A clock generator for generating a clock phase-synchronized with a sync. signal in a video signal, comprising: (a) phase comparison means for phase-comparing the clock having the same frequency as the sync. signal and the sync. signal; (b) controlled oscillation means having an oscillation frequency thereof controlled in accordance with the output of said phase comparison means, said clock being generated by using an output of said controlled oscillation means; (c) first control means for maintaining a control input to said controlled oscillation means at a predetermined level according to a reproducing speed of the video signal; and (d) second control means for synchronizing the clock with the sync. signal during the operation of said first control means.
Claim 11
Dependent Claim
118 words
A clock generator for generating a clock phase-synchronized with a sync. signal in a video signal, comprising: (a) phase comparison means for phase-comparing the clock having the same frequency as the sync. signal and the sync. signal; (b) controlled oscillation means having an oscillation frequency thereof controlled in accordance with the output of said phase comparison means, said clock being generated by using an output of said controlled oscillation means; (c) first control means for maintaining a control input to said controlled oscillation means at a predetermined level according to a reproducing speed of the video signal; and (d) second control means for synchronizing the clock with the sync. signal during the operation of said first control means.
Claim 12
Independent Claim
217 words
An apparatus for correcting a time base of a video signal reproduced from a recording medium, comprising: (a) separating means for separating a sync signal in the video signal; (b) phase-synchronizing means for generating a first clock synchronized with the separated sync. signal and having the same frequency as the separated sync. signal, said phase-synchronizing means including phase-comparing means for phase-comparing the separated sync. signal and the first clock, selecting means for selectively outputting the output level of said phase-comparing means or a predetermined level, oscillating means for generating a second clock having an oscillation frequency thereof controlled in accordance with the output of said selecting means and frequency-dividing means for frequency-dividing the second clock to generate the first clock; (c) control means for causing said selecting means to output the predetermined level when the video signal is reproduced at a different speed than that in a record mode, said control means resetting said frequency-dividing means in accordance with the sync. signal separated by said separating means while the video signal is reproduced at the different speed than that in the record mode, said selecting means selecting the predetermined level according to the reproducing speed of the video signal; and (d) correcting means for correcting a time base of the video signal by using the second clock.
Claim 13
Independent Claim
217 words
An apparatus for correcting a time base of a video signal reproduced from a recording medium, comprising: (a) separating means for separating a sync signal in the video signal; (b) phase-synchronizing means for generating a first clock synchronized with the separated sync. signal and having the same frequency as the separated sync. signal, said phase-synchronizing means including phase-comparing means for phase-comparing the separated sync. signal and the first clock, selecting means for selectively outputting the output level of said phase-comparing means or a predetermined level, oscillating means for generating a second clock having an oscillation frequency thereof controlled in accordance with the output of said selecting means and frequency-dividing means for frequency-dividing the second clock to generate the first clock; (c) control means for causing said selecting means to output the predetermined level when the video signal is reproduced at a different speed than that in a record mode, said control means resetting said frequency-dividing means in accordance with the sync. signal separated by said separating means while the video signal is reproduced at the different speed than that in the record mode, said selecting means selecting the predetermined level according to the reproducing speed of the video signal; and (d) correcting means for correcting a time base of the video signal by using the second clock.
Claim 14
Independent Claim
234 words
An apparatus for correcting a time base of a video signal comprising: (a) input means for inputting a video signal having a vertical sync. signal and other sync. signal; (b) separating means for separating the other sync. signal from the video signal; (c) phase-synchronizing means for generating a first clock synchronized with the other sync. signal and having the same frequency as the other sync. signal; said phase-synchronizing means including phase-comparing means for phase-comparing the other sync. signal and the first clock, sampling and holding means for sampling and holding an output level of said phase-comparing means; oscillating means for generating a second clock having an oscillation frequency thereof controlled in accordance witch an output of said sampling and holding means and frequency-dividing means for frequency-dividing the second clock to generate the first clock; (d) detecting means for detecting a dropout of the video signal; (e) control means for controlling said sampling and holding means in accordance with an output of said detecting means during the dropout of the video signal and resetting said frequency-dividing means in accordance with the other sync. signal, the controlling operation of said sampling and holding means and the resetting operation of said frequency-dividing means by said control means operating to regulate said phase-synchronizing means irrespective of the vertical sync. signal; and (f) correcting means for correcting a time base of the video signal by using the second clock.
Claim 15
Independent Claim
234 words
An apparatus for correcting a time base of a video signal comprising: (a) input means for inputting a video signal having a vertical sync. signal and other sync. signal; (b) separating means for separating the other sync. signal from the video signal; (c) phase-synchronizing means for generating a first clock synchronized with the other sync. signal and having the same frequency as the other sync. signal; said phase-synchronizing means including phase-comparing means for phase-comparing the other sync. signal and the first clock, sampling and holding means for sampling and holding an output level of said phase-comparing means; oscillating means for generating a second clock having an oscillation frequency thereof controlled in accordance witch an output of said sampling and holding means and frequency-dividing means for frequency-dividing the second clock to generate the first clock; (d) detecting means for detecting a dropout of the video signal; (e) control means for controlling said sampling and holding means in accordance with an output of said detecting means during the dropout of the video signal and resetting said frequency-dividing means in accordance with the other sync. signal, the controlling operation of said sampling and holding means and the resetting operation of said frequency-dividing means by said control means operating to regulate said phase-synchronizing means irrespective of the vertical sync. signal; and (f) correcting means for correcting a time base of the video signal by using the second clock.
Claim 16
Dependent Claim
46 words
A clock generator according to claim 9, further comprising: frequency-dividing means for frequency-dividing the output of said controlled oscillation means to generate the clock, said second control means synchronizing the clock with the sync. signal by resetting said frequency-dividing means in accordance with the sync. signal.
Claim 17
Dependent Claim
31 words
An apparatus according to claim 11, wherein said detecting means detects the dropout of the video signal by detecting a dropout of a horizontal synchronization signal included in the video signal.
Claim 18
Dependent Claim
46 words
An apparatus according to claim 11, further comprising reproduction means for reproducing the video signal from a recording medium, and wherein said detecting means detects the dropout of the video signal according to a RF signal corresponding to the video signal reproduced by said reproduction means.
Claim 19
Dependent Claim
148 words
A clock signal generating device, comprising: (a) input means for inputting a video signal having a vertical sync. signal and other sync. signal; (b) generating means for generating a clock signal phase-synchronized with the other sync. signal, said generating means including phase detection means for detecting phase difference between said clock signal and the other sync. signal and controlled oscillation means having an oscillation frequency thereof controlled in accordance with the output of said phase detection means, said clock being generated by using an output of said controlled oscillation means; (c) first control means for maintaining a control input to said oscillating means at a constant level according to a dropout of the video signal; and (d) second control means for synchronizing the clock signal to the other sync. signal, said first and second control means operating to regulate said generating means irrespective of the vertical synchronization signal.
Claim 20
Dependent Claim
148 words
A clock signal generating device, comprising: (a) input means for inputting a video signal having a vertical sync. signal and other sync. signal; (b) generating means for generating a clock signal phase-synchronized with the other sync. signal, said generating means including phase detection means for detecting phase difference between said clock signal and the other sync. signal and controlled oscillation means having an oscillation frequency thereof controlled in accordance with the output of said phase detection means, said clock being generated by using an output of said controlled oscillation means; (c) first control means for maintaining a control input to said oscillating means at a constant level according to a dropout of the video signal; and (d) second control means for synchronizing the clock signal to the other sync. signal, said first and second control means operating to regulate said generating means irrespective of the vertical synchronization signal.
Claim 21
Dependent Claim
17 words
A device according to claim 15, further comprising means for detecting a dropout of the video signal.
Claim 22
Dependent Claim
43 words
A device according to claim 15, wherein said first control means includes holding means for holding an output of said phase detection means, and wherein the oscillation frequency of said controlled oscillation means is controlled according to an output of said holding means.
Claim 23
Dependent Claim
37 words
A device according to claim 15, further comprising frequency dividing means for frequency dividing an output of said controlled oscillation means, wherein said second control means resets said frequency dividing means according to said input synchronization signal.
Claim 24
Dependent Claim
110 words
A clock generator for generating a clock phase-synchronized with a video signal, comprising: (a) phase detecting means for detecting phase difference between the clock and an input video signal; (b) controlled oscillation means having an oscillation frequency thereof in accordance with the output of said phase comparison means, said clock being generated by using an output of said controlled oscillation means; (c) first control means for maintaining a control input to said controlled oscillation means at a predetermined level according to a reproducing speed of the video signal; and (d) second control means for synchronizing the clock with the input video signal during the operation of said first control means.
Claim 25
Dependent Claim
110 words
A clock generator for generating a clock phase-synchronized with a video signal, comprising: (a) phase detecting means for detecting phase difference between the clock and an input video signal; (b) controlled oscillation means having an oscillation frequency thereof in accordance with the output of said phase comparison means, said clock being generated by using an output of said controlled oscillation means; (c) first control means for maintaining a control input to said controlled oscillation means at a predetermined level according to a reproducing speed of the video signal; and (d) second control means for synchronizing the clock with the input video signal during the operation of said first control means.
Claim 26
Dependent Claim
31 words
A clock generator according to claim 19, further comprising a memory for storing a video signal and writing means for writing the input video signal into the memory using the clock.
Claim 27
Dependent Claim
45 words
A clock generator according to claim 9, wherein the video signal is reproduced from a recording medium, and said second control means synchronizes the clock with the sync. signal when the video signal is reproduced at a different speed than that in a record mode.
References Cited (Backward Citations)
US4092672A
Cited
US4692914A
Cited
US4815061A
Cited
JPS62139478A
Cited
JPS6474083A
Cited
JPH0276383A
Cited
JPH03119881A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-06-18 | 1999-12-18 | 2000-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-06-18 | 2003-12-18 | 2004-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-06-18 | 2007-12-18 | 2008-06-18 | $7700.00 | Window Closed / Lapsed |