Patent EP0049136A2 successfully refreshed from Google Patents.
EP0049136A2
Expired / Lapsed
EP
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Rotational speed controlling apparatus for recording disc
Assignee: Toshiba Corp
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Filing: 1981-09-25
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Granted: —
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Expires: 2001-09-25
Abstract
Abstract An apparatus for controlling the rotational speed of a recording disc (22) to a constant linear velocity. The apparatus has frequency control circuit (24, 28, 30, 50, 52) and a phase control circuit (24, 28, 30, 32, 34, 38, 40, 42, 46) which detect the variations of the frequency and phase of the digital information signal reproduced from the disc, to detect the rotation speed of the disc. The rotation of the disc is controlled in response to the control signals from the frequency and phase controle circuits to a constant linear velocity.
Inventors
- 👤 Daiki Nabeshima
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 20:21
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/10; G11B20/10527; G11B19/00; G11B19/20; G11B19/24
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
226 words
An apparatus for controlling a rotational speed of a recording disc in reproducing an information signal pre-recorded on said disc as a train of pulses, said information signal being a digital signal including a synchronizing signal and pre-recorded while said disc is rotating with a constant linear velocity, comprising: a motor (20) for rotating said recording disc (22); means (24, 28) for reproducing said information signal pre-recorded on said disc; means (38) for extracting said synchronizing signal from said information signal reproduced by said reproducing means; phase comparing means (40) for comparing the phases between said synchronizing signal and a reference signal and generating a phase difference signal in response to the difference of phases between said synchronizing signal and said reference signal, said reference signal having a predetermined phase relationship to said synchronizing signal while said disc is rotated with a constant linear velocity; detecting means (30) for detecting the leading and trailing edges of the pulses of said information signal reproduced by said reproducing means and generating a signal having constant amplitude and pulse width; smoothing means (50) for smoothing said signal from said detecting means; means (48) for adding the signals from said smoothing means and from said phase comparing means; and motor driving means (44) for controlling the rotation speed of said motor in response to the signal from said adding means.
Claim 2
Independent Claim
226 words
An apparatus for controlling a rotational speed of a recording disc in reproducing an information signal pre-recorded on said disc as a train of pulses, said information signal being a digital signal including a synchronizing signal and pre-recorded while said disc is rotating with a constant linear velocity, comprising: a motor (20) for rotating said recording disc (22); means (24, 28) for reproducing said information signal pre-recorded on said disc; means (38) for extracting said synchronizing signal from said information signal reproduced by said reproducing means; phase comparing means (40) for comparing the phases between said synchronizing signal and a reference signal and generating a phase difference signal in response to the difference of phases between said synchronizing signal and said reference signal, said reference signal having a predetermined phase relationship to said synchronizing signal while said disc is rotated with a constant linear velocity; detecting means (30) for detecting the leading and trailing edges of the pulses of said information signal reproduced by said reproducing means and generating a signal having constant amplitude and pulse width; smoothing means (50) for smoothing said signal from said detecting means; means (48) for adding the signals from said smoothing means and from said phase comparing means; and motor driving means (44) for controlling the rotation speed of said motor in response to the signal from said adding means.
Claim 3
Dependent Claim
59 words
An apparatus according to claim 1, wherein said reproducing means comprises: a signal detector (24) for detecting the digital information pre-recorded on said disc; and a compartor (28), connected to said signal detector, for comparing the output voltage level of said signal detector with a predetermined voltage level to shape the waveform of the signal from said signal detector.
Claim 4
Dependent Claim
15 words
An apparatus according to claim 1, wherein said smoothing means is a low-pass filter (50).
Claim 5
Dependent Claim
67 words
An apparatus according to claim 1, wherein said phase comparing means comprises: a phase comparator (40) for comparing the phases between said synchronizing signal and said reference signal; and a low-pass filter (46), connected to said phase compartor, for filtering the signal from said phase comparator to generate the phase difference signal in response to the difference of phases between said synchronizing signal and said reference signal.
Claim 6
Dependent Claim
15 words
An apparatus according to claim 4, wherein said phase comparator (40) is an exclusive-OR circuit.
Claim 7
Dependent Claim
90 words
An apparatus according to claim 1, wherein said detection means (30) comprises: a first differentiating circuit (60) for differentiating an input signal; a second differentiating circuit (62) for differentiating an inverted signal of said input signal; a logic circuit (66), connected to said first and second differentiating circuits, for each passing one polarity of signal in the output signals from said first and second differentiating circuits; and a monostable multivibrator (68), connected to said logic circuit, for generating a signal in response to the output signal of said logic circuit.
Claim 8
Dependent Claim
65 words
An apparatus according to claim 1, further comprising: a phase locked loop circuit (32), connected to said detecting means, for generating a signal synchronized with the output signal of said detecting means (30); and a demodulation circuit (34), connected to said phase locked loop circuit, for demodulating the information signal from said detecting means in synchronizing with the signal from said phase locked loop circuit.
Claim 9
Dependent Claim
43 words
An apparatus according to claim 1, further comprising: a switching means (70) for interrupting in a given position the connection between said motor driving means and said phase comparing means; and a control circuit (72) for causing said switching means to switch selectively.
Claim 10
Dependent Claim
24 words
An apparatus according to claim 8, wherein said switching means (70) is provided between said phase comparing means (40) and said adding means (48).
Claim 11
Dependent Claim
42 words
An apparatus according to claim 8, wherein said switching means (70) connects said smoothing means (50) to said motor driving means (44) in a first position and connects said adding means (48) to said motor driving means (44) in a second position.
Claim 12
Dependent Claim
30 words
An apparatus according to claim 7, further comprising a data processing circuit (36), connected to said demodulation circuit, for restoring said demodulated digital information signal to an analog information signal.
Claim 13
Dependent Claim
65 words
An apparatus according to claim 11, wherein said data processing circuit comprises: means (76, 78) for correcting or interpolating errors in said demodulated information signal; a memory circuit (80) for storing the signal from said error correcting or interpolating means and reading it out therefrom; and a digital-to-analog converter (84) for converting the read-out digital signal from said memory circuit into the analog information signal.
Claim 14
Dependent Claim
76 words
An apparatus according to claim 1 or 12, further comprising: a master clock generator (70); a first counter (72) for counting down an output signal generated by said master clock generator and supplying its output signal as said reference signal to said phase comparing means; and a second counter (74) for counting down said output signal generated by said master clock generator and supplying its output signal as a read-out control signal to said memory circuit.
References Cited (Backward Citations)
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