EP0136816A2
Expired / Lapsed
EP
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Apparatus for controlling delay times at the time of a changed speed reproduction mode
Assignee: Victor Company of Japan Ltd
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Filing: 1984-08-28
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Granted: —
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Expires: 2004-08-28
Abstract
Abstract A delay time control apparatus comprises a comparing circuit (60) for comparing levels of reproduced frequency modulated signals from a pair of rotary heads which simultaneously scan over a magnetic tape, where the rotary heads have gaps of mutually different azimuth angles, a head selecting circuit (48) responsive to an output signal of the comparing circuit, for selectively producing the reproduced signal from the rotary head having a larger level, a signal processing circuit (53-57) for obtaining a reproduced video signal from the reproduced signal which is selectively produced from the head selecting circuit, a variable delay circuit (77) for delaying the reproduced video signal from the signal processing circuit by a delay time, and a delay control signal generating circuit (72) for variably controlling the delay time of the variable delay circuit so that the variable delay produces a reproduced video signal in which reproduced horizontal synchronizing signals have a constant period.
Inventors
- 👤 Yasuomi Namiki
- 👤 Koji Arai
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 05:41
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/79; H04N9/7921; G; G11; G11B; G11B27/00; G11B27/005; H04N9/87; H04N9/89; G11B15/00; G11B15/02; G11B15/05; G11B15/087; G11B15/12; G11B15/125; G11B15/18; G11B15/1808; G11B15/1875; G11B2220/00; G11B2220/90
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
408 words
A delay time control apparatus characterized in that there are provided: comparing means (H L1 , H L2 , H S1 , H S2' 41-46, 49-52, 60) for comparing levels of reproduced frequency modulated signals produced from one predetermined pair of rotary heads (H Ll & H S2 , or H L2 & H Sl ) among a plurality of pairs of rotary heads (H L1 , H L2 , H S1 , HS2), said predetermined pair of rotary heads simultaneously scanning over a magnetic tape (35) which moves at a tape moving speed which is different from a tape moving speed of the magnetic tape at the time of a recording, each pair of said plurality of pairs of rotary heads having gaps of mutually different azimuth angles and being arranged close to each other, said magnetic tape having a track pattern in which a video signal is frequency-modulated and recorded at the time of the recording by rotary heads having gaps of mutually different azimuth angles and recorded positions of horizontal synchronizing signals are shifted in the longitudinal direction of tracks and are not aligned between mutually adjacent tracks; head selecting means (48, 67, 68, 69) responsive to an output signal of said comparing means, for selectively producing the reproduced signal produced from one of said predetermined pair of rotary heads, said reproduced signal produced from the one of said predetermined pair of rotary heads having a level which is larger than a level of the reproduced signal produced from the other of said predetermined pair of rotary heads; signal processing means (53-55, 76) for subjecting the reproduced signal which is selectively produced from said head selecting means to a signal processing, and for obtaining a reproduced video signal; a variable delay circuit (77) for delaying the reproduced video signal from said signal processing means by a delay time; and a delay control signal generating circuit (72) supplied with a head selection signal obtained from a part of said head selecting means and mode signals indicative of a reproducing mode, said head selection signal indicating said one rotary head which is producing the reproduced signal with the larger level, said delay control signal generating circuit generating control signals responsive to the signals supplied thereto, and variably controlling the delay time of said variable delay circuit so that said variable delay circuit produces a reproduced video signal in which reproduced horizontal synchronizing signals have a constant period.
Claim 2
Dependent Claim
408 words
A delay time control apparatus characterized in that there are provided: comparing means (H L1 , H L2 , H S1 , H S2' 41-46, 49-52, 60) for comparing levels of reproduced frequency modulated signals produced from one predetermined pair of rotary heads (H Ll & H S2 , or H L2 & H Sl ) among a plurality of pairs of rotary heads (H L1 , H L2 , H S1 , HS2), said predetermined pair of rotary heads simultaneously scanning over a magnetic tape (35) which moves at a tape moving speed which is different from a tape moving speed of the magnetic tape at the time of a recording, each pair of said plurality of pairs of rotary heads having gaps of mutually different azimuth angles and being arranged close to each other, said magnetic tape having a track pattern in which a video signal is frequency-modulated and recorded at the time of the recording by rotary heads having gaps of mutually different azimuth angles and recorded positions of horizontal synchronizing signals are shifted in the longitudinal direction of tracks and are not aligned between mutually adjacent tracks; head selecting means (48, 67, 68, 69) responsive to an output signal of said comparing means, for selectively producing the reproduced signal produced from one of said predetermined pair of rotary heads, said reproduced signal produced from the one of said predetermined pair of rotary heads having a level which is larger than a level of the reproduced signal produced from the other of said predetermined pair of rotary heads; signal processing means (53-55, 76) for subjecting the reproduced signal which is selectively produced from said head selecting means to a signal processing, and for obtaining a reproduced video signal; a variable delay circuit (77) for delaying the reproduced video signal from said signal processing means by a delay time; and a delay control signal generating circuit (72) supplied with a head selection signal obtained from a part of said head selecting means and mode signals indicative of a reproducing mode, said head selection signal indicating said one rotary head which is producing the reproduced signal with the larger level, said delay control signal generating circuit generating control signals responsive to the signals supplied thereto, and variably controlling the delay time of said variable delay circuit so that said variable delay circuit produces a reproduced video signal in which reproduced horizontal synchronizing signals have a constant period.
Claim 3
Dependent Claim
293 words
A delay time control apparatus as claimed in claim 1, characterized in that said magnetic tape is recorded with a frequency modulated luminance signal and a frequency converted carrier chrominance signal, said frequency modulated luminance signal being a luminance signal of a PAL or SECAM system color video signal and being frequency-modulated, said frequency converted carrier chrominance signal being a carrier chrominance signal of the PAL or SECAM system color video signal and being frequency-converted into a low frequency band; that said signal processing means comprises luminance signal reproducing means (53, 55) for demodulating a reproduced frequency modulated luminance signal and for subjecting a demodulated signal to a predetermined signal processing, carrier chrominance signal reproducing means (54) for obtaining from a reproduced frequency converted carrier chrominance signal a reproduced carrier chrominance signal which is in an original frequency band, variable delay means (56, 57) for selectively delaying the reproduced carrier chrominance signal from said carrier chrominance signal reproducing means or the reproduced frequency converted carrier chrominance signal by a delay time of one horizontal scanning period, and a mixing circuit (76) for mixing the reproduced luminance signal from said luminance signal reproducing means and the reproduced carrier chrominance signal which is selectively delayed in said variable delay means and is returned to the original frequency band; and that said delay control signal generating circuit comprises means for generating first and second control signals, supplying said first control signals to said variable delay circuit, supplying said second control signal to said variable delay means so as to variably control the delay time of said variable delay means, and producing the reproduced carrier chrominance signal or the reproduced frequency converted carrier chrominance signal having a chrominance sequence which is corrected by said variable delay means.
Claim 4
Dependent Claim
105 words
A delay time control apparatus as claimed in claim 1, characterized in that there are further provided an integrating circuit (61) for integrating the output signal of said comparing means, and a signal generating circuit (63) supplied with an output signal of said integrating circuit, for generating a signal in synchronism with a frequency component which is related to a number of times said predetermined pair of rotary heads scan across the tracks on the magnetic tape, and for supplying the signal to said head selecting means; and that said head selecting means compares the signal from said signal generating circuit and a reference voltage.
Claim 5
Dependent Claim
122 words
A delay time control apparatus as claimed in claim 3, characterized in that said signal generating circuit comprises a phase locked loop (63) which is constituted by a variable frequency oscillator (65) having a center frequency which is related to the number of times said predetermined pair of rotary heads scan across the tracks on the magnetic tape, and a phase comparator (64) for comparing the phase of an output signal of said variable frequency oscillator and the phase of the output signal of said integrating circuit, and for supplying a signal which is dependent on a phase difference between the two signals to said variable frequency oscillator so as to variably control an output oscillation frequency of said variable frequency oscillator.
Claim 6
Dependent Claim
56 words
A delay time control apparatus as claimed in claim 4, characterized in that said center frequency of said variable frequency oscillator is set responsive to an output voltage of a voltage generator (16) which generates the output voltage responsive to capstan rotation detection pulses having a repetition frequency dependent on a rotational speed of a capstan.
Claim 7
Dependent Claim
63 words
A delay time control apparatus as claimed in claim 1, characterized in that said head selecting means selectively produces the reproduced signal from one of said predetermined pair of rotary heads having a wider track width than the other rotary head, for a period which is longer than a period in which the reproduced signal from said other rotary head is selectively produced.
Claim 8
Dependent Claim
41 words
A delay time control apparatus as claimed in claim 1, characterized in that said comparing means comprises highpass filter means (58, 59) for comparing levels of high-frequency components of the reproduced frequency modulated signals from said predetermined pair of rotary heads.
Claim 9
Dependent Claim
41 words
A delay time control apparatus as claimed in claim 1, characterized in that said predetermined pair of rotary heads are arranged with a separation which is within several times the recording length of one horizontal scanning period on the magnetic tape.
Claim 10
Dependent Claim
53 words
A delay time control apparatus as claimed in claim 8, characterized in that said predetermined pair of rotary heads are made up of a double-gap head comprising a rotary head for extended time mode play having a small track width and a rotary head for standard mode play having a large track width.
Claim 11
Dependent Claim
256 words
A delay time control apparatus as claimed in claim 2, characterized in that said delay control signal generating circuit comprises a waveform shaping circuit (131, 132, 133 , 134, D 1 , D 2' D 4 , D 5 , D 6 , R 1 ) for producing a first signal having a phase which is the same or is inverted compared to the phase of said head selection signal during a high-speed reproduction mode depending on a moving direction of the magnetic tape, first frequency dividing means (142) for frequency-dividing the output first signal of said waveform shaping circuit by 1/2, second frequency dividing means (143, 144) for producing a second signal having a phase which is the same or is inverted compared to the phase of an output signal of said first frequency dividing means depending on the moving direction of the magnetic tape, and for frequency-dividing the second signal by 1/2, means (R 4 , D 9 , D 10 , 139-141, 73) for producing an output signal of said second frequency dividing means as said second control signal during the high-speed reproduction mode, and means (D 1 , 131, 74, 75) for producing said head selection signal and the output signal of said first frequency dividing means as said first control signals, and for variably controlling the delay time of said variable delay circuit to one of four kinds of delay times depending on a logical combination of said head selection signal and the output signal of said first frequency dividing means.
References Cited (Backward Citations)
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