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Patent US4549226A successfully refreshed from Google Patents.
US4549226A
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Eliminating the low-frequency chrominance signal for tracking in a video tape recorder
Assignee: Panasonic Holdings Corp
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Filing: 1982-10-08
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Granted: 1985-10-22
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Expires: 2002-10-08
Abstract
Abstract An automatic tracking apparatus, by which a tracking condition of reproducing heads and a recorded track can be automatically adjusted. This apparatus has a rotary heads, an envelope detector, and a filter. A tracking error signal is generated by detecting the envelope of a video signal which does not contain chrominance signal components, the video signal being derived from the rotary heads. As a result, the tracking error signal includes only the luminance signal but does not include the signal from the next track. Therefore, the envelope signal is a good tracking error signal which is only responsive to the signal level of the objective track.
Inventors
- 👤 Masao Tomita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 11:43
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/48; G11B5/58; G11B5/584; G11B5/588; G11B5/592
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
151 words
In an automatic tracking system which is used in a video tape recorder having two rotary heads different in azimuth from each other and which moves the rotary heads to keep them on-track according to a tracking error signal obtained from an envelope of a video signal which is reproduced by the rotary heads and is composed of a chrominance signal converted to a low-frequency and a luminance signal, said envelope being detected by an envelope detecting means coupled to the rotary heads the improvement comprising a filter means disposed between said heads and said envelope detecting means for eliminating the low-frequency converted chrominance signal so as to increase the S/N ratio of the tracking error signal with respect to a cross-talk signal, so that said envelope detected by said envelope detector substantially includes only an envelope of the luminance signal, whereby the S/N of the tracking error signal is improved.
Claim 2
Dependent Claim
151 words
In an automatic tracking system which is used in a video tape recorder having two rotary heads different in azimuth from each other and which moves the rotary heads to keep them on-track according to a tracking error signal obtained from an envelope of a video signal which is reproduced by the rotary heads and is composed of a chrominance signal converted to a low-frequency and a luminance signal, said envelope being detected by an envelope detecting means coupled to the rotary heads the improvement comprising a filter means disposed between said heads and said envelope detecting means for eliminating the low-frequency converted chrominance signal so as to increase the S/N ratio of the tracking error signal with respect to a cross-talk signal, so that said envelope detected by said envelope detector substantially includes only an envelope of the luminance signal, whereby the S/N of the tracking error signal is improved.
Claim 3
Dependent Claim
31 words
An automatic tracking system according to claim 1, wherein said filter means comprises a trap circuit composed of a coil and a capacitor which are connected in series with each other.
Claim 4
Dependent Claim
29 words
The automatic tracking system according to claim 1, wherein said filter means comprises a band elimination filter for eliminating frequency components in a band centered at about 629 kHz.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-10-21 | 1989-04-22 | 1989-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-21 | 1993-04-22 | 1993-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-21 | 1997-04-22 | 1997-10-22 | $7700.00 | Window Closed / Lapsed |