Patent EP0075948A2 successfully refreshed from Google Patents.
EP0075948A2
Expired / Lapsed
EP
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Playback speed control system
Assignee: Hitachi Ltd
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Filing: 1982-09-29
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Granted: —
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Expires: 2002-09-29
Abstract
Abstract Disclosed is a disc (1) or tape signal reproducing apparatus having a first speed control loop (1-3, 15, 13, 8-10) in which the duration of a specific pulse in the PCM signal recorded on the disc or tape is detected and the current sync signal interval is anticipated from the duration of the pulse so that the motor speed is pulled into the operation range of the sync signal detector (5), and a second speed control loop (1-5, 8-10, 13) which controls the motor (3) speed basing on the sync signal reproduced by the sync signal detector (5). The motor speed is controlled by the first speed control loop until the sync signal detector detects the sync signal, thereafter the motor speed is controlled by the second speed control loop basing on the reproduced sync signal.
Inventors
- 👤 Hiroyuki Maedachoshigaichijutaku Kimura
- 👤 Yoshimi Shirakawa-Apartment House 333 Iso
- 👤 Shigeki Inoue
- 👤 Takashi Takeuchi
- 👤 Shinichi Ohashi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 11:13
CPC Classifications
G; G11; G11B; G11B19/00; G11B19/20; G11B19/24
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
100 words
A reproduction speed control system for a signal reproducing apparatus having a speed control system which controls the reproduction speed in accordance with a signal obtained by comparing the output of a speed detection means with a reference signal, wherein said speed detection means is a circuit means which receives a reproduction signal and provides a plurality of reproduction speed signals, one of said reproduction speed signals being selected by a switch means, said selected speed detection signal being fed back to a control object so that it is compared with said reference signal to thereby control the reproduction speed.
Claim 2
Dependent Claim
100 words
A reproduction speed control system for a signal reproducing apparatus having a speed control system which controls the reproduction speed in accordance with a signal obtained by comparing the output of a speed detection means with a reference signal, wherein said speed detection means is a circuit means which receives a reproduction signal and provides a plurality of reproduction speed signals, one of said reproduction speed signals being selected by a switch means, said selected speed detection signal being fed back to a control object so that it is compared with said reference signal to thereby control the reproduction speed.
Claim 3
Dependent Claim
96 words
A reproduction speed control system according to Claim 1, wherein said signal reproduction system is a signal reproduction system for a recording medium on which are recorded digital data including syncronizing signals, said plurality of reproduction speed detection means comprising a synchronizing signal detector (5) and a specific pulse detector (11) which detects specific pulses in a reproduced signal, said switch means selecting the output of said specific pulse detector during the operation outside the detection range for the synchronizing signals, while selecting the output of said synchronizing signal detector, thereby to control the reproduction speed.
Claim 4
Dependent Claim
83 words
A reproduction speed control system according to Claim 2, wherein said specific pulse detector comprises a specific pulse width detector (15) which detects the duration of a specific pulse and a pseudo synchronizing signal generator (15b - 15d) which generates a pseudo synchronizing signal in accordance with the duration of said specific pulse, output of said synchronizing signal detector and output of said pseudo synchronizing signal generator being switched in such a way that at least a frequency-to-voltage converter (8) is used commonly.
Claim 5
Dependent Claim
27 words
A reproduction speed control system according to Claim 2, wherein the detection period of said specific pulse detector is longer than the period of said synchronizing signal.
Claim 6
Dependent Claim
27 words
A reproduction speed control system according to Claim 3, wherein the detection period of said specific pulse detector is longer than the period of said synchronizing signal.
Claim 7
Dependent Claim
62 words
A reproduction speed control system according to Claim 3, wherein the dynamic range of said frequency-to-voltage cnnverter is set to be wider than the range of synchronizing signal detected by said synchronizing signal detection circuit, the frequency variation range of the pseudo synchronizing signal generated by said pseudo synchronizing signal generator being made narrower than the dynamic range of said frequency-to-voltage converter.
Claim 8
Dependent Claim
63 words
A reproduction speed control system according to Claim 2, further comprising a memory means (31, 35, 36) \ for storing a speed detection signal before switching, a switching control signal for said switch means being entered to a timer circuit, which provides an output so that the speed detection signal before switching is fed back to said control object for a certain period.
References Cited (Backward Citations)
No citation records indexed.
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