Patent US3925810A successfully refreshed from Google Patents.
US3925810A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording and/or reproducing system
Assignee: Sony Corp
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Filing: 1975-01-21
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Granted: 1975-12-09
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Expires: 1995-01-21
Abstract
Abstract In reducing crosstalk between the low frequency, frequencyconverted chrominance portions of h-aligned video signals on adjacent tracks, the frequency converting carrier, but not the entire frequency converted portion, has its polarity inverted at the end of each line interval during the recording of alternate tracks but not during the recording of the remaining alternate tracks. This eliminates the extraneous signal that would otherwise be produced in the balanced modulator of the playback apparatus by any direct voltage offset or transient remanent of a direct voltage offset in the recorded signal.
Inventors
- 👤 Yoshio Ishigaki
- 👤 Hisaaki Narahara
- 👤 Takao Tsuchiya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 14:59
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/79; H04N9/80; H04N9/82; H04N9/83; H04N9/84
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
103 words
Apparatus in which video signals are recorded in h-alignment in adjacent tracks on a recording medium, said apparatus comprising: A. means for generating a frequency converting carrier signal in first and second versions of opposite polarity; B. a frequency converter to receive chrominance components of said video signals; and C. means to apply said first and second versions of said carrier signal in a predetermined sequence to said frequency converter, said sequence being such that, during alternate tracks, only one of said versions is applied and, during the remaining alternate tracks, said first and second versions are applied alternately in successive line intervals.
Claim 2
Dependent Claim
103 words
Apparatus in which video signals are recorded in h-alignment in adjacent tracks on a recording medium, said apparatus comprising: A. means for generating a frequency converting carrier signal in first and second versions of opposite polarity; B. a frequency converter to receive chrominance components of said video signals; and C. means to apply said first and second versions of said carrier signal in a predetermined sequence to said frequency converter, said sequence being such that, during alternate tracks, only one of said versions is applied and, during the remaining alternate tracks, said first and second versions are applied alternately in successive line intervals.
Claim 3
Dependent Claim
79 words
The apparatus of claim 1 in which said carrier generating means comprises: A. an oscillator to generate said carrier signal; B. a double-throw switching circuit comprising first and second input terminals connected to receive said first and second versions of said carrier signal, said switching circuit comprising an output terminal that can be conductively connected to said first and second input terminals alternately; and C. a filter connecting said output terminal of said switching circuit to said frequency converter.
Claim 4
Dependent Claim
34 words
The apparatus of claim 1 comprising: A. a low pass filter connected to said frequency converter; and B. transducer means connected to said filter to record the frequency converted signals on said recording medium.
Claim 5
Dependent Claim
93 words
The apparatus of claim 3 comprising: A. a second frequency converter a connected to said means to apply said carrier signal, whereby said second converter receives said first and second versions in said predetermined sequence; B. switching means to connect said transducer means alternatively to receive frequency converted signals from said first-named frequency converter and to supply reproduced signals from said recording medium to said second frequency converter; and C. a comb filter connected to said second frequency converter to filter interleaved cross-talk components from desired, frequency converted chrominance signals of opposite polarity.
Claim 6
Dependent Claim
43 words
The apparatus of claim 1 comprising: A. reproduCing transducer means to play back information recorded on said recording medium; and B. a comb filter connected to said frequency converter to filter interleaved cross-talk components from desired, frequency converted chrominance signals of opposite polarity.
References Cited (Backward Citations)
US3821787A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-08 | 1979-06-09 | 1979-12-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-08 | 1983-06-09 | 1983-12-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-08 | 1987-06-09 | 1987-12-09 | $7700.00 | Window Closed / Lapsed |