Patent EP0289046A2 successfully refreshed from Google Patents.
EP0289046A2
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Jitter-detecting apparatus for a video tape recorder
Assignee: Sharp Corp
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Filing: 1988-04-29
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Granted: —
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Expires: 2008-04-29
Abstract
Abstract An improved jitter detecting method and an apparatus thereof, for detecting a jitter generated in a reproduced video signal of a VTR or video disc wherein a frequency-modulated carrier of a video signal is recorded by synchronizing the leading edge of a sync signal with the phase of the forefront carrier of a constant frequency carrier train corresponding to a sync tip for every horizontal period at the time of a frequency-modulation, and from the reproduced frequency-modulated carrier the phase-reset constant frequency carrier train is abstracted as a reference burst signal, thereby to be capable of removing a time-base error by detecting a specifie zero-crossing timing of the abtracted carrier burst through a bandpass filter based on the tailing edge of a frequency-modulated sync signal at the reproduction.
Inventors
- 👤 Soichi Iwamura
- 👤 Satoshi Murakami
- 👤 Masakazu Ishikawa
- 👤 Naoki Koide
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 02:46
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/10; G11B20/18; H; H04; H04N; H04N9/00; H04N9/79; H04N9/87; H04N9/89; H04N9/896; H04N9/893
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
132 words
A jitter detecting method, for detecting a jitter generated in a video signal recorded and reproduced by multiplying a luminance signal and a chrominance signal in the time bases thereof, comprising the steps of: recording a frequency-modulated carrier of video signal by synchronizing the phase of the leading edge of a sync signal with the phase of the initial carrier of the constant frequency carrier corresponding to a sync tip of the video signal for every horizontal period prior to the recording; detecting the jitter of said reproduced video signal by detecting a specific zero-cross timing of a train of the constant frequency carrier corresponding to the sync tip portion through a band pass filter (23), based on the tailing edge of a frequency-demodulated sync signal at the time of a reproduction.
Claim 2
Dependent Claim
132 words
A jitter detecting method, for detecting a jitter generated in a video signal recorded and reproduced by multiplying a luminance signal and a chrominance signal in the time bases thereof, comprising the steps of: recording a frequency-modulated carrier of video signal by synchronizing the phase of the leading edge of a sync signal with the phase of the initial carrier of the constant frequency carrier corresponding to a sync tip of the video signal for every horizontal period prior to the recording; detecting the jitter of said reproduced video signal by detecting a specific zero-cross timing of a train of the constant frequency carrier corresponding to the sync tip portion through a band pass filter (23), based on the tailing edge of a frequency-demodulated sync signal at the time of a reproduction.
Claim 3
Dependent Claim
159 words
A jitter detecting apparatus for detecting a jitter generated in a video signal recorded and reproduced by performing the time division multiplex or the frequency division multiplex of a luminance signal and a chrominance signal wherein: a frequency modulation recording is performed by synchronizing the phase of the leading edge of a sync signal or a phase in the vicinity thereof with the phase of the initial carrier of the corresponding constant frequency carrier for every horizontal period; a phase-continuous compensating signal for preventing the frequency-modulated carrier's phase from abruption is inserted into the front porch of said sync signal when the phase thereof is synchronized and a jitter of a reproduced video signal is detected by detecting a specific zero cross timing of a train of the constant frequency carrier corresponding to said sync tip portion through a narrow band pass filter, based on the tailing edge of a frequency-demodulated sync signal at the time of a reproduction.
Claim 4
Dependent Claim
159 words
A jitter detecting apparatus for detecting a jitter generated in a video signal recorded and reproduced by performing the time division multiplex or the frequency division multiplex of a luminance signal and a chrominance signal wherein: a frequency modulation recording is performed by synchronizing the phase of the leading edge of a sync signal or a phase in the vicinity thereof with the phase of the initial carrier of the corresponding constant frequency carrier for every horizontal period; a phase-continuous compensating signal for preventing the frequency-modulated carrier's phase from abruption is inserted into the front porch of said sync signal when the phase thereof is synchronized and a jitter of a reproduced video signal is detected by detecting a specific zero cross timing of a train of the constant frequency carrier corresponding to said sync tip portion through a narrow band pass filter, based on the tailing edge of a frequency-demodulated sync signal at the time of a reproduction.
Claim 5
Dependent Claim
170 words
A time base error detecting/correcting method comprising the steps of: replacing part or all of the blanking period of a video signal including a sync signal with a noiseless sync signal generated in a sync generator gen-locking the input video signal before the video signal is recorded in a video tape recorder so as to detect and correct a time base error; resetting the phase of the forefront carrier in a train of the constant frequency carrier train to a constant value at the leading edge of the replaced sync signal, when a frequency modulation is performed to record the video signal in a recording medium; abstracting the constant frequency carrier portion corresponding to the sync tip from a reproduced frequency modulation carrier by means of the frequency-demodulated sync signal, and detecting a time error signal by abstracting the phase-reset carrier of a constant frequency present in the portion corresponding to the sync tip from the reproduced frequency modulation carrier as a reference burst at the time of a reproduction.
Claim 6
Dependent Claim
170 words
A time base error detecting/correcting method comprising the steps of: replacing part or all of the blanking period of a video signal including a sync signal with a noiseless sync signal generated in a sync generator gen-locking the input video signal before the video signal is recorded in a video tape recorder so as to detect and correct a time base error; resetting the phase of the forefront carrier in a train of the constant frequency carrier train to a constant value at the leading edge of the replaced sync signal, when a frequency modulation is performed to record the video signal in a recording medium; abstracting the constant frequency carrier portion corresponding to the sync tip from a reproduced frequency modulation carrier by means of the frequency-demodulated sync signal, and detecting a time error signal by abstracting the phase-reset carrier of a constant frequency present in the portion corresponding to the sync tip from the reproduced frequency modulation carrier as a reference burst at the time of a reproduction.
References Cited (Backward Citations)
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