US4510530A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Signal reproducing circuit for a video tape recorder
Assignee: Hitachi Ltd
•
Filing: 1982-06-18
•
Granted: 1985-04-09
•
Expires: 2002-06-18
Abstract
Abstract In a FM luminance signal circuit of a signal reproducing circuit of a video tape recorder, (a) a reproduced signal is up-converted by an up-converter, the up-converted signal is divided into two frequency components by a surface acoustic wave filter having a first filter for peaking a high frequency component and a second filter for peaking a low frequency component, a limiter connected to the first filter, an amplifier connected to the second filter, and an adder of an output of a limiter and an output of an amplifier, and the reversal of the levels of the FM carrier signal and side band signal is prevented by above configuration. (b) A side-band glass delay line of 1H (one horizontal scan period) is provided to get 1H delayed luminance signal. Using main luminance signal and 1H delayed luminance signal, a line correlation circuit and a video dropout compensation circuit are realized. (c) In a PAL signal reproducing circuit, where a chrominance signal is delayed by 1H by a comb filter using 2H delay line, 1H delayed luminance signal is used to prevent a chrominance displacement from the luminance signal.
Inventors
- 👤 Kuniaki Miura
- 👤 Akira Shibata
- 👤 Jun Yamada
- 👤 Katashi Hazama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 12:38
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/76; H04N5/91; H04N5/93; H04N5/94; G; G11; G11B; G11B5/00; G11B5/02; H04N5/931; H04N5/9315; H04N9/00; H04N9/79; H04N9/87
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
85 words
A signal reproducing circuit in a video tape recorder comprising, in an FM luminance signal circuit, an up-converter for up-converting a reproduced signal; a surface acoustic wave filter connected to the output of said up-converter, and said surface acoustic wave filter including a parallel circuit of a first filter for mainly peaking a high frequency component and a second filter for mainly peaking a low frequency component; and an adder for adding an output of said first filter and an output of said second filter.
Claim 2
Dependent Claim
85 words
A signal reproducing circuit in a video tape recorder comprising, in an FM luminance signal circuit, an up-converter for up-converting a reproduced signal; a surface acoustic wave filter connected to the output of said up-converter, and said surface acoustic wave filter including a parallel circuit of a first filter for mainly peaking a high frequency component and a second filter for mainly peaking a low frequency component; and an adder for adding an output of said first filter and an output of said second filter.
Claim 3
Dependent Claim
92 words
A signal reproducing circuit according to claim 1, further comprising, in the FM luminance signal circuit, a limiter and an amplifier; said limiter and said amplifier being connected to outputs of said first and second filters respectively, when an up-conversion frequency of said up-converter is lower than a center frequency of said first or second filter; and said limiter and said amplifier being connected to outputs of said second and first filter, respectively when said up-conversion frequency is equal to or higher than the center frequency of said first or second filter.
Claim 4
Dependent Claim
115 words
A signal reproducing circuit in a video tape recorder comprising in an FM luminance signal circuit, an up-converter for up-converting a reproduced signal; a surface acoustic wave filter connected to an output of said up-converter, and said surface acoustic wave filter having a parallel circuit of a first filter for mainly peaking a high frequency component and a second filter for mainly peaking a low frequency component; a limiter connected to an output of said first filter of said surface acoustic wave filter; an amplifier connected to an output of said second filter of said acoustic surface wave filter; and an adder for adding an output of said limiter and an output of said amplifier.
Claim 5
Dependent Claim
115 words
A signal reproducing circuit in a video tape recorder comprising in an FM luminance signal circuit, an up-converter for up-converting a reproduced signal; a surface acoustic wave filter connected to an output of said up-converter, and said surface acoustic wave filter having a parallel circuit of a first filter for mainly peaking a high frequency component and a second filter for mainly peaking a low frequency component; a limiter connected to an output of said first filter of said surface acoustic wave filter; an amplifier connected to an output of said second filter of said acoustic surface wave filter; and an adder for adding an output of said limiter and an output of said amplifier.
Claim 6
Dependent Claim
59 words
A signal reproducing circuit in a video tape recorder comprising, in an FM luminance signal circuit, an up-converter for up-converting a reproduced signal; a surface acoustic wave filter for equalizing the up-converted signal; and an FM signal drop-out compensation circuit including a wide-band 1H (one horizontal scan period) glass delay line for compensating a drop-out of the reproduced signal.
Claim 7
Dependent Claim
59 words
A signal reproducing circuit in a video tape recorder comprising, in an FM luminance signal circuit, an up-converter for up-converting a reproduced signal; a surface acoustic wave filter for equalizing the up-converted signal; and an FM signal drop-out compensation circuit including a wide-band 1H (one horizontal scan period) glass delay line for compensating a drop-out of the reproduced signal.
Claim 8
Dependent Claim
109 words
A signal reproducing circuit in a video tape recorder comprising, in an FM luminance signal circuit, an up-converter in an FM luminance signal circuit for up-converting a reproduced signal; a surface acoustic wave filter for equalizing an up-converted signal; an FM signal drop-out compensation circuit including a wide-band 1H (one horizontal scan period) glass delay line for compensating a dropout of the reproduced signal; a pair of demodulators for separately demodulating the signal prior to the passage of said 1H-delay line and the signal after the passage of said 1H-delay line; and a line correlation circuit and a video dropout compensation circuit using outputs of said pair of demodulators.
Claim 9
Dependent Claim
109 words
A signal reproducing circuit in a video tape recorder comprising, in an FM luminance signal circuit, an up-converter in an FM luminance signal circuit for up-converting a reproduced signal; a surface acoustic wave filter for equalizing an up-converted signal; an FM signal drop-out compensation circuit including a wide-band 1H (one horizontal scan period) glass delay line for compensating a dropout of the reproduced signal; a pair of demodulators for separately demodulating the signal prior to the passage of said 1H-delay line and the signal after the passage of said 1H-delay line; and a line correlation circuit and a video dropout compensation circuit using outputs of said pair of demodulators.
Claim 10
Dependent Claim
35 words
A signal reproducing circuit according to claim 5 wherein said surface acoustic filter includes a first filter for mainly peaking a high frequency component and a second filter for mainly peaking a low frequency component.
Claim 11
Dependent Claim
55 words
A signal reproducing circuit according to claim 4 or 5 further comprising a comb filter using a 2H-delay line which delays a chroma signal by 1H-period, wherein said signal demodulated after the passage of said 1H-delay line in a FM luminance circuit is used as a PAL FM luminance signal when no drop-out is present.
Claim 12
Dependent Claim
36 words
A signal reproducing circuit according to claim 7 wherein said surface acoustic wave filter includes a first filter for mainly peaking a high frequency component and a second filter for mainly peaking a low frequency component.
Claim 13
Dependent Claim
19 words
A signal reproducing circuit according to claim 3 or 5 wherein an up-conversion frequency of said up-converter is variable.
Claim 14
Dependent Claim
31 words
A signal reproducing circuit accoridng to claim 3 or 5 further comprising an automatic gain control circuit located before said up-converter or between said up-converter and said surface acoustic wave filter.
References Cited (Backward Citations)
US4245262A
Cited
US4368483A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-04-08 | 1988-10-08 | 1989-04-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-04-08 | 1992-10-08 | 1993-04-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-04-08 | 1996-10-08 | 1997-04-09 | $7700.00 | Window Closed / Lapsed |