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US4562394A
Expired / Lapsed
US
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Motor servo circuit for a magnetic recording and reproducing apparatus
Assignee: Victor Company of Japan Ltd
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Filing: 1984-11-13
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Granted: 1985-12-31
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Expires: 2004-11-13
Abstract
Abstract A motor servo circuit is used in a recording and reproducing apparatus which comprises a loop including a comparator for comparing the phases of a signal which is responsive to the rotation of a motor and a reference signal and for controlling the rotation of the motor responsive to an output error signal. The circuit comprises an oscillator for producing a signal having a frequency which is higher than a frequency of the reference signal, a counter for counting the output of the oscillator, which counter resets itself when a full count ff is reached and is reset when a reset signal is applied thereto before the full count ff is reached, a circuit for detecting that the count has reached a first value C1 (C1<ff), and for supplying the reference signal to the comparator, a circuit for detecting that the count has reached a second value C2 (C1<C2<ff) and a third value C3 (C3<C1), and for producing a gate signal during a time period it takes for the count to reach the third value C3 from the second value C2, and a gate circuit responsive to the gate signal, for supplying a vertical synchronizing signal within an input video signal which is to be recorded on a recording medium by the apparatus to the counter as the reset signal.
Inventors
- 👤 Kenji Itoh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:31
CPC Classifications
G; G11; G11B; G11B15/00; G11B15/18; G11B15/46; H; H02; H02P; H02P23/00; H02P23/18; H02P23/186; Y; Y10; Y10S; Y10S388/00; Y10S388/907; Y10S388/912; Y10S388/915
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
296 words
A motor servo circuit for a magnetic recording and reproducing apparatus which comprises a loop including phase comparing means for comparing the phase of a signal which is responsive to the rotation of a motor with the phase of a reference signal and for controlling the rotation of the motor responsive to an error signal which is obtained as a result of the phase comparison, said motor servo circuit comprising: oscillator means for producing a signal having a frequency which is higher than a frequency of the reference signal; a counter for counting the output signal of the oscillator means, said counter resetting itself when a counted value reaches a full count and being reset when a reset signal is applied thereto before the full count is reached; a first detecting circuit for detecting that the counted value in the counter has reached a first counted value which is smaller than the full count, and for supplying the reference signal to the phase comparator means; a second detecting circuit for detecting that the counted value in the counter has reached a second counted value which is larger than the first counted value and is smaller than the full count and a third counted value which is smaller than the first counted value, and for producing a gate signal during a time period it takes for the counted value in the counter to reach the third counted value from the second counted value, said time period including therein a time when the counter is reset; and a gate circuit responsive to the gate signal, for supplying a vertical synchronizing signal within an input video signal which is to be recorded on a recording medium by the recording and reproducing apparatus to the counter as the reset signal.
Claim 2
Dependent Claim
296 words
A motor servo circuit for a magnetic recording and reproducing apparatus which comprises a loop including phase comparing means for comparing the phase of a signal which is responsive to the rotation of a motor with the phase of a reference signal and for controlling the rotation of the motor responsive to an error signal which is obtained as a result of the phase comparison, said motor servo circuit comprising: oscillator means for producing a signal having a frequency which is higher than a frequency of the reference signal; a counter for counting the output signal of the oscillator means, said counter resetting itself when a counted value reaches a full count and being reset when a reset signal is applied thereto before the full count is reached; a first detecting circuit for detecting that the counted value in the counter has reached a first counted value which is smaller than the full count, and for supplying the reference signal to the phase comparator means; a second detecting circuit for detecting that the counted value in the counter has reached a second counted value which is larger than the first counted value and is smaller than the full count and a third counted value which is smaller than the first counted value, and for producing a gate signal during a time period it takes for the counted value in the counter to reach the third counted value from the second counted value, said time period including therein a time when the counter is reset; and a gate circuit responsive to the gate signal, for supplying a vertical synchronizing signal within an input video signal which is to be recorded on a recording medium by the recording and reproducing apparatus to the counter as the reset signal.
Claim 3
Dependent Claim
70 words
A motor servo circuit as claimed in claim 1 in which the value of said full count is set so that a timing with which the counter resets itself when the counter value reaches the full count, is the same as a timing with which the counter is reset by the vertical synchronizing signal within the input video signal when the vertical synchronizing signal is obtained in a normal manner.
Claim 4
Dependent Claim
104 words
A motor servo circuit as claimed in claim 1 in which said counter comprises a plurality of flip-flops which are coupled in series, each of said plurality of flip-flops having a reset terminal, and a first AND gate having input terminals coupled to output terminals of first predetermined flip-flops among said plurality of flip-flops, said first AND gate detecting that all of Q-outputs of said first predetermined flip-flops exist when said plurality of flip-flops perform counting until the full count is reached and supplying an output signal to the reset terminals of said plurality of flip-flops so as to reset said plurality of flip-flops.
Claim 5
Dependent Claim
83 words
A motor servo circuit as claimed in claim 3 in which said first detecting circuit comprises a second AND gate having input terminals coupled to output terminals of second predetermined flip-flops among said plurality of flip-flops, said second AND gate detecting that all of Q-outputs of said second predetermined flip-flops exist and producing an output signal, and a first other flip-flop having a set terminal applied with the output signal of the second AND gate, said first other flip-flop producing the reference signal.
Claim 6
Dependent Claim
122 words
A motor servo circuit as claimed in claim 4 in which said second detecting circuit comprises a third AND gate having input terminals coupled to output terminals of third predetermined flip-flops among said plurality of flip-flops, said third AND gate detecting that all of Q-outputs of said third predetermined flip-flops exist, a fourth AND gate having input terminals coupled to output terminals of fourth predetermined flip-flops among said plurality of flip-flops, said fourth AND gate detecting that all of Q-outputs of said fourth predetermined flip-flops exist, and a second other flip-flop having a reset terminal supplied with an output of said third AND gate and a set terminal supplied with an output of said fourth AND gate, for producing said gate signal.
Claim 7
Dependent Claim
63 words
A motor servo circuit as claimed in claim 5 in which said gate circuit comprises a fifth AND gate supplied with said gate signal, a recording mode signal, and the vertical synchronizing signal within said input video signal, said fifth AND gate producing an output signal which is supplied to the reset terminals of all of said plurality of flip-flops in said counter.
Claim 8
Dependent Claim
66 words
A motor servo circuit as claimed in claim 6 in which said counter is supplied with the output signals of said first and fifth AND gates, and said counter further comprises an OR gate for producing an output signal which is supplied to the reset terminals of all of said plurality of flip-flops in said counter and to a reset terminal of said first other flip-flop.
References Cited (Backward Citations)
US4243921A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-12-30 | 1989-07-01 | 1989-12-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-12-30 | 1993-07-01 | 1993-12-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-12-30 | 1997-07-01 | 1997-12-31 | $7700.00 | Window Closed / Lapsed |