US3873900A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Servo drive for a rotating system
Assignee: US Philips Corp
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Filing: 1974-01-07
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Granted: 1975-03-25
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Expires: 1994-01-07
Abstract
Abstract A control circuit for a rotating object, such as is found in a tape recorder, has two control loops. The first takes the output signal of a phase detector, which is dependent upon a phase difference, between a reference source and the rotating object, and applies it to a speed control means. The second loop converts the phase detector output signal into a signal that is dependent upon a frequency difference and the duration of the frequency difference and applies it to the speed control means.
Inventors
- 👤 Friedrich Sommer
- 👤 Uwe Jahnke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:27
CPC Classifications
H; H02; H02P; H02P29/00; H02P29/0016; H02P29/0022; H02P23/00; H02P23/18; H02P23/183; Y; Y10; Y10S; Y10S388/00; Y10S388/90; Y10S388/901; Y10S388/902
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
236 words
Servo drive for a rotating system which comprises a phase detector for determining the phase difference between first and second input signals, one of said signals comprising a sawtooth signal, means coupled to said phase detector for generating said first input signal, said first signal comprising a measuring signal the frequency of which is representative of the speed of the rotating system, means coupled to said phase detector for generating said second input signal said second signal comprising a reference signal the frequency of which is representative of the desired speed, the output signal from the phase detector being applied, via a first transmission path, as a first control signal to a control device adapted to be coupled to said system for controlling the speed of the rotating system, the phase detector comprising means for sampling said sawtooth signal at sampling instants which are in synchronism with the other input signal and a means for storing the sampled values, said stored values comprising the output signal from the phase detector, a second transmission path shunting said first path, which sEcond path comprises at least one differentiator for differentiating the output signal from the phase detector, the output of this differentiator being connected to a summing device in which the successive peak values of the output signal from this differentiator are summed, the resulting sum signal being applied to the control device as a second control signal.
Claim 2
Dependent Claim
236 words
Servo drive for a rotating system which comprises a phase detector for determining the phase difference between first and second input signals, one of said signals comprising a sawtooth signal, means coupled to said phase detector for generating said first input signal, said first signal comprising a measuring signal the frequency of which is representative of the speed of the rotating system, means coupled to said phase detector for generating said second input signal said second signal comprising a reference signal the frequency of which is representative of the desired speed, the output signal from the phase detector being applied, via a first transmission path, as a first control signal to a control device adapted to be coupled to said system for controlling the speed of the rotating system, the phase detector comprising means for sampling said sawtooth signal at sampling instants which are in synchronism with the other input signal and a means for storing the sampled values, said stored values comprising the output signal from the phase detector, a second transmission path shunting said first path, which sEcond path comprises at least one differentiator for differentiating the output signal from the phase detector, the output of this differentiator being connected to a summing device in which the successive peak values of the output signal from this differentiator are summed, the resulting sum signal being applied to the control device as a second control signal.
Claim 3
Dependent Claim
46 words
Servo drive as claimed in claim 1, where said second transmission path comprises two differentiators to the inputs of which the same input signal is applied and the outputs of which are connected to the summing device via circuit elements which pass signals of opposite polarities.
Claim 4
Dependent Claim
50 words
Servo drive as claimed in claim 1, wherein at the output of the second transmission path there is provided at least one non-linear circuit element for limiting the effect of the output voltage of the summing device before one of the two driving limits of the control circuits is reached.
Claim 5
Dependent Claim
79 words
Servo drive as claimed in claim 3, wherein the outputs of the two transmission paths are connected to a first input of an operational amplifier which is provided to feed the control device and the second input of which is connected to a reference voltage source for the control circuit and to a threshold value switch is connected to the summing device and is closed before the driving limits of the operational amplifier and/or the control device are reached.
Claim 6
Dependent Claim
58 words
Servo drive as claimed in claim 4, wherein the second input of the operational amplifier is also connected to a voltage limiter which when the driving limits of the operational amplifier and/or the control device are reached holds the potential at the second input of the operational amplifier at the value which corresponds to the relevant driving limit.
References Cited (Backward Citations)
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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) | 1978-03-24 | 1978-09-23 | 1979-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-24 | 1982-09-23 | 1983-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-24 | 1986-09-23 | 1987-03-25 | $7700.00 | Window Closed / Lapsed |