US3983316A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Turntable speed control system
Assignee: RCA Corp
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Filing: 1975-03-17
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Granted: 1976-09-28
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Expires: 1995-03-17
Abstract
Abstract In a video disc system for recovering prerecorded signals from a disc record by a signal pickup including a turntable, turntable drive means, and turntable speed adjusting means, a turntable speed control system is provided for maintaining the rotation of the turntable at a predetermined speed. Means responsive to the rotation of the turntable generate sample pulses having a frequency which is a function of the actual speed of rotation of the turntable. The sample pulse occur at a predetermined frequency when the turntable is rotating at the predetermined speed. Means are employed for generating a sawtooth-shaped reference wave having a frequency which is a multiple of the predetermined frequency. A sample-and-hold circuit is coupled to the sample pulse generating means and reference wave generating means for determining the magnitude of the reference wave during the occurrence of each of the sample pulses for developing a speed error correction signal. The magnitude of the speed error correction signal is a function of the phase deviation between the sample pulse train and the reference wave. The adjusting means coupled to the sample-and-hold circuit and responsive to the speed error correction signal maintain the rotation of the turntable at the predetermined speed.
Inventors
- 👤 James Conrad Schopp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 12:35
CPC Classifications
H; H02; H02P; H02P29/00; H02P29/0016; H02P29/0022; G; G11; G11B; G11B19/00; G11B19/20; G11B19/24; H02P23/00; H02P23/22; Y; Y10; Y10S; Y10S388/00; Y10S388/90; Y10S388/901; Y10S388/907; Y10S388/915
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
370 words
In a system for playing back prerecorded information by a signal pickup from a disc record when relative motion is established therebetween; the playback system including a turntable for rotatably supporting the disc record; wherein for accurate reproduction of the prerecorded signals, a predetermined speed of rotation of the turntable is desired; the playback system including drive means for driving the turntable to rotate at a free running speed above the predetermined speed; adjusting means coupled to the drive means and responsive to a speed error correction signal for maintaining the speed of rotation of the turntable at the predetermined speed during playback; the system further including a signal processing circuit responsive to signals developed at the output of the signal pickup; the signal processing circuit including means for effecting frequency stabilization of components of the developed signals; a turntable speed control system comprising: 1. means responsive to the rotation of the turntable for generating a train of speed indicating pulses having a frequency which is a multiple, including one, of the actual speed of rotation of the turntable; the speed indicating pulses occurring at a predetermined frequency when the speed of rotation of the turntable is at the predetermined speed; 2. means for generating generally sawtooth-shaped reference waves having a frequency which is a greater-than-one multiple of the predetermined frequency of the speed indicating pulses; the reference wave generating means comprising an oscillator, a frequency divider responsive to the output of the oscillator, and an integrator circuit responsive to the output of the frequency divider for developing the sawtooth-shaped reference waves; the output of the oscillator being additionally supplied to the frequency stabilization effecting means; 3. means coupled to the speed indicating pulse generating means and the reference wave generating means, and responsive to the magnitude of the reference wave during the occurrence of each of the speed indicating pulses, for developing a speed error correction signal; the magnitude of the speed error correction signal being a function of the phase deviation between the speed indicating pulse train and the reference wave; and 4. means for supplying the speed error correction signal to the adjusting means for adjusting the speed of rotation of the turntable to the predetermined speed.
Claim 2
Dependent Claim
370 words
In a system for playing back prerecorded information by a signal pickup from a disc record when relative motion is established therebetween; the playback system including a turntable for rotatably supporting the disc record; wherein for accurate reproduction of the prerecorded signals, a predetermined speed of rotation of the turntable is desired; the playback system including drive means for driving the turntable to rotate at a free running speed above the predetermined speed; adjusting means coupled to the drive means and responsive to a speed error correction signal for maintaining the speed of rotation of the turntable at the predetermined speed during playback; the system further including a signal processing circuit responsive to signals developed at the output of the signal pickup; the signal processing circuit including means for effecting frequency stabilization of components of the developed signals; a turntable speed control system comprising: 1. means responsive to the rotation of the turntable for generating a train of speed indicating pulses having a frequency which is a multiple, including one, of the actual speed of rotation of the turntable; the speed indicating pulses occurring at a predetermined frequency when the speed of rotation of the turntable is at the predetermined speed; 2. means for generating generally sawtooth-shaped reference waves having a frequency which is a greater-than-one multiple of the predetermined frequency of the speed indicating pulses; the reference wave generating means comprising an oscillator, a frequency divider responsive to the output of the oscillator, and an integrator circuit responsive to the output of the frequency divider for developing the sawtooth-shaped reference waves; the output of the oscillator being additionally supplied to the frequency stabilization effecting means; 3. means coupled to the speed indicating pulse generating means and the reference wave generating means, and responsive to the magnitude of the reference wave during the occurrence of each of the speed indicating pulses, for developing a speed error correction signal; the magnitude of the speed error correction signal being a function of the phase deviation between the speed indicating pulse train and the reference wave; and 4. means for supplying the speed error correction signal to the adjusting means for adjusting the speed of rotation of the turntable to the predetermined speed.
Claim 3
Dependent Claim
71 words
A system as defined in claim 1 wherein the turntable includes a conductive portion, and the adjusting means comprise a magnitude field generating structure situated adjacent to the turntable and responsive to the speed error correction signal for establishing eddy currents in the conductive turntable portion, and wherein the eddy currents develop a braking force in a manner that adjusts the speed of rotation of the turntable to the predetermined speed.
Claim 4
Dependent Claim
54 words
A system as defined in claim 1 wherein the speed indicating pulse generating means include a ferromagnetic insert affixed to the periphery of the turntable, a permanent magnet positioned near the periphery of the turntable, and a coil wound on the permanent magnet for detecting change in flux for developing the speed indicating pulses.
Claim 5
Dependent Claim
46 words
A system as defined in claim 1 wherein the speed error correction signal developing means include a sample-and-hold circuit for determining and retaining the magnitude of the reference wave during the occurrence of each of the speed indicating pulses for developing the speed error correction signal.
Claim 6
Dependent Claim
25 words
A system as defined in claim 1 wherein the frequency of the speed indicating pulses is equal to the speed of rotation of the turntable.
Claim 7
Dependent Claim
54 words
A system as defined in claim 1 further including means for suppressing the speed error correction signal supplying means during generation of the speed indicating pulses for a short interval of time after the drive means are initially switched on for playback to facilitate the drive means to quickly approach the free running speed.
Claim 8
Dependent Claim
54 words
A system as defined in claim 1 further including means for augmenting the speed error correction signal supplied to the adjusting means to develop maximum opposition to rotation of the turntable for a short interval of time after the drive means are switched off following playback to bring the turntable to a quick stop.
Claim 9
Dependent Claim
27 words
A system as defined in claim 1 wherein the frequency of the reference wave is a 13-or-under multiple of the predetermined frequency of the speed indicating pulses.
Claim 10
Independent Claim
99 words
A system for recovering prerecorded information from a disc record by a signal pickup when relative motion is established therebetween comprising the combination of: 1. a turntable for rotatably supporting the disc record; a predetermined speed of rotation of the turntable being desireable for accurate reproduction of the prerecorded information; 2. driving means for driving the turntable to rotate at a free running speed above the predetermined speed; 3. adjusting means coupled to the drive means and responsive to a speed error correction signal for maintaining the speed of rotation of the turntable at the predetermined speed during playback;
Claim 11
Independent Claim
99 words
A system for recovering prerecorded information from a disc record by a signal pickup when relative motion is established therebetween comprising the combination of: 1. a turntable for rotatably supporting the disc record; a predetermined speed of rotation of the turntable being desireable for accurate reproduction of the prerecorded information; 2. driving means for driving the turntable to rotate at a free running speed above the predetermined speed; 3. adjusting means coupled to the drive means and responsive to a speed error correction signal for maintaining the speed of rotation of the turntable at the predetermined speed during playback;
Claim 12
Dependent Claim
253 words
an oscillator; 5. a signal processing circuit responsive to signals developed at the output of the signal pickup; the signal processing circuit including means responsive to an output of the oscillator for effecting frequency stabilization of components of the developed signals; 6. means responsive to the rotation of the turntable for generating a train of speed indicating pulses having a frequency which is a multiple, including one, of the actual speed of rotation of the turntable; the speed indicating pulses occurring at a predetermined frequency when the speed of rotation of the turntable is at the predetermined speed; 7. means for generating generally sawtooth-shaped reference waves having a frequency which is a greater-than-one, but less-than-14, multiple of the predetermined frequency of the speed indicating pulses; the reference wave generating means including a frequency divider responsive to the output of the oscillator, and an integrator circuit responsive to the output of the frequency divider for developing the sawtooth-shaped reference waves; 8. means coupled to the speed indicating pulse generating means and the reference wave generating means, and responsive to the magnitude of the reference wave during the occurrence of each of the speed indicating pulses, for developing a speed error correction signal; the magnitude of the speed error correction signal being a function of the phase deviation between the speed indicating pulse train and the reference wave; and 9. means for supplying the speed error correction signal to the adjusting means for adjusting the speed of rotation of the turntable to the predetermined speed.
Claim 13
Dependent Claim
253 words
an oscillator; 5. a signal processing circuit responsive to signals developed at the output of the signal pickup; the signal processing circuit including means responsive to an output of the oscillator for effecting frequency stabilization of components of the developed signals; 6. means responsive to the rotation of the turntable for generating a train of speed indicating pulses having a frequency which is a multiple, including one, of the actual speed of rotation of the turntable; the speed indicating pulses occurring at a predetermined frequency when the speed of rotation of the turntable is at the predetermined speed; 7. means for generating generally sawtooth-shaped reference waves having a frequency which is a greater-than-one, but less-than-14, multiple of the predetermined frequency of the speed indicating pulses; the reference wave generating means including a frequency divider responsive to the output of the oscillator, and an integrator circuit responsive to the output of the frequency divider for developing the sawtooth-shaped reference waves; 8. means coupled to the speed indicating pulse generating means and the reference wave generating means, and responsive to the magnitude of the reference wave during the occurrence of each of the speed indicating pulses, for developing a speed error correction signal; the magnitude of the speed error correction signal being a function of the phase deviation between the speed indicating pulse train and the reference wave; and 9. means for supplying the speed error correction signal to the adjusting means for adjusting the speed of rotation of the turntable to the predetermined speed.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-09-28 | 1980-03-29 | 1980-09-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-28 | 1984-03-29 | 1984-09-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-28 | 1988-03-29 | 1988-09-28 | $7700.00 | Window Closed / Lapsed |