Patent US3617209A successfully refreshed from Google Patents.
EP0102809A1
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Magnetic reproducing apparatus
Assignee: Panasonic Holdings Corp
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Filing: 1983-08-24
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Granted: —
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Expires: 2003-08-24
Abstract
Abstract A magnetic reproducing apparatus which has two main rotatable heads (M M 2 ) having different azimuth angles and two auxiliary rotatable heads (S 1 , S 2 ) having different azimuth angles. When a magnetic tape (6) is played back at a speed different from that at which was recorded, playback output signals from the main and auxiliary rotatable heads are switched over to replace a reduction in the outputs from the main rotatable heads (M 1 , M 2 ) with the outputs from the auxiliary rotatable heads (S 1 , S 2 ) to produce a combined playback output signal. The combined playback output signal is passed through a variable delay line (30,71) having a delay time varied by an output from a detector cricuit (72) which detects variations in horizontal synchronous signal intervals of the combined playback output signal. This varied delay time of the variable delay line can eliminate any skew distortions which would appear on a displayed image on the screen due to the variations in horizontal synchronous signal intervals of the combined playback output signal.
Inventors
- 👤 Tokikazu Matsumoto
- 👤 Masahiro Honjo
- 👤 Masaaki Kobayashi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 17:49
CPC Classifications
G; G11; G11B; G11B15/00; G11B15/02; G11B15/12; G11B15/14; G11B20/00; G11B20/20; G11B5/00; G11B5/48; G11B5/52; G11B5/53; G11B5/531; H; H04; H04N; H04N5/00; H04N5/76; H04N5/78; H04N5/782; H04N5/783; H04N5/91; H04N5/93; H04N5/95; H04N5/953
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
265 words
A magnetic reproducing apparatus comprising: two main rotatable heads (M 1 , M2) having different azimuth angles; two auxiliary rotatable heads (S 1 , S 2 ) having different azimuth angles and attached in different positions from those of said main rotatable heads; switching timing control means (66) for controlling timing of switching between playback output signals from said main (M 1 , M 2 ) and auxiliary (S 1 , S 2 ) rotatable heads when a magnetic tape (6) runs in a playback mode at a speed different from that at which the magnetic tape (6) runs in a recording mode; switching means (22, 23) responsive to an output signal from said switching timing control means (66) for replacing the playback output signals from said main rotatable heads (M 1 , M 2 ) with the playback output signals from said auxiliary rotatable heads (S 1 , S 2 ) to thereby produce a combined playback output signal; a variable delay line (30) for passing said combined playback output signals therethrough; detector means (72) for detecting the period of a reproduced horizontal synchronous signal when said combined playback output signals pass through said variable delay line; and delay time control means (39,60) responsive to an output signal from said detector circuit (72) for varying a delay time of said variable delay line (30) thereby to remove any skew generated when the playback output signals from said main rotatable heads (M 1 , M 2 i are replaced with the playback output signals form said auxiliary rotatable heads (S 1 , S 2 )
Claim 2
Dependent Claim
265 words
A magnetic reproducing apparatus comprising: two main rotatable heads (M 1 , M2) having different azimuth angles; two auxiliary rotatable heads (S 1 , S 2 ) having different azimuth angles and attached in different positions from those of said main rotatable heads; switching timing control means (66) for controlling timing of switching between playback output signals from said main (M 1 , M 2 ) and auxiliary (S 1 , S 2 ) rotatable heads when a magnetic tape (6) runs in a playback mode at a speed different from that at which the magnetic tape (6) runs in a recording mode; switching means (22, 23) responsive to an output signal from said switching timing control means (66) for replacing the playback output signals from said main rotatable heads (M 1 , M 2 ) with the playback output signals from said auxiliary rotatable heads (S 1 , S 2 ) to thereby produce a combined playback output signal; a variable delay line (30) for passing said combined playback output signals therethrough; detector means (72) for detecting the period of a reproduced horizontal synchronous signal when said combined playback output signals pass through said variable delay line; and delay time control means (39,60) responsive to an output signal from said detector circuit (72) for varying a delay time of said variable delay line (30) thereby to remove any skew generated when the playback output signals from said main rotatable heads (M 1 , M 2 i are replaced with the playback output signals form said auxiliary rotatable heads (S 1 , S 2 )
Claim 3
Dependent Claim
52 words
A magnetic reproducing apparatus according to claim 1, wherein said detector means (72) comprises a feedback loop composed of a phase comparator (47), a voltage-controlled oscillator (42) and a low-pass filter (43), said phase comparator (47) being responsive to the horizontal synchronous signal for producing an output signal indicative of said skew.
Claim 4
Dependent Claim
121 words
A magnetic reproducing apparatus according to claim 1 or 2, wherein said delay time control means (Figure 6) comprises an arithmetic circuit (60) for successively accumulating outputs from said detector means (72) and a voltage-control oscillator (70) for producing an output -having an oscillation frequency variable in response to .an output voltage from said arithmetic circuit (60), said variable delay line (30) comprising a charge-coupled device delay line having a delay time variable by the oscillation frequency from said voltage-controlled oscillator (20), said voltage-controlled oscillator (70) being controllable by said arithmetic circuit (60) to set the delay time of said charge-coupled device delay line (30) as the value at a mid-point of a variable delay-time range in each vertical synchronous period.
Claim 5
Dependent Claim
125 words
A magnetic reproducing apparatus according to claim 1 or 2, wherein said delay time control means (Figure 8) comprises an arithmetic circuit (60) for successively accumulating outputs from said detector means (72), a comparator (35) for comparing an output voltage from said arithmetic circuit (60) with a reference voltage (36), and switching means (31) switchable in response to an output from said comparator (35), said variable delay line comprising a tapped delay line (71) having taps switchable by said switching means (31) to vary a delay time of the variable delay line (71), said arithmetic circuit (60) being capable of producing an output voltage such that said switching means (31) selects a middle tap of said tapped delay line (71) in each vertical synchronous period.
Claim 6
Dependent Claim
73 words
A magnetic reproducing apparatus according to any one of the preceding claims, wherein said switching timing control means (66) comprises a level detector (82) for detecting the levels of the playback output signals from said main (M 1 ,M 2 ) and auxiliary rotatable heads (S 1 , S 2 ), said main and auxiliary rotatable heads being switchable over at a timing controlled by an output (65) from said level detector (82).
Claim 7
Dependent Claim
50 words
A magnetic reproducing apparatus according to claim 1, wherein said switching timing control means (66) is responsive to a rotary angle of said main (M 1 , M 2 ) or auxiliary (S1, S 2 )rotatable heads for controlling the timing of switching between said main and auxiliary rotatable heads.
Claim 8
Dependent Claim
36 words
A magnetic reproducing apparatus according to any one of the preceding claims, wherein said horizontal synchronous signal is derived from the combined playback output signal before the latter passes through said variable delay line (30, 71).
Claim 9
Dependent Claim
36 words
- A magnetic reproducing apparatus according to any one of the preceding claims, wherein said horizontal synchronous signal is derived from the combined playback output signal after the latter has passed through said variable delay line.
References Cited (Backward Citations)
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