US3821604A
Expired / Lapsed
US
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Arrangement for synchronizing two signals
Assignee: US Philips Corp
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Filing: 1972-12-26
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Granted: 1974-06-28
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Expires: 1992-12-26
Abstract
Abstract Arrangement for synchronizing a measuring signal produced by a controllable generator with a reference signal. For motor speed control the generator is a system which is coupled to the motor shaft and provides a measuring signal the frequency of which is a measure of the motor speed. The arrangement includes a fourposition counter the count of which is increased one position by each reference pulse and is reduced one position by each measuring pulse. The arrangement further includes a sawtooth generator which provides a signal which is in synchronism with the reference signal and is applied to a logic circuit. This logic circuit is so controlled by the four-position counter as to provide an output signal which, after sampling at instants which correspond to the measuring pulses, produces a control signal which has an extreme value if the frequencies of the measuring and reference signals are different and has a value determined by the phase difference if the frequencies are equal. The great advantage of the arrangement is that the motor speed is adjustable over a wide range without stability problems arising.
Inventors
- 👤 A Walraven
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 00:22
CPC Classifications
H; H03; H03L; H03L7/00; H03L7/06; H03L7/08; H02; H02P; H02P23/00; H02P23/18; H02P23/186; Y; Y10; Y10S; Y10S388/00; Y10S388/90; Y10S388/901; Y10S388/907; Y10S388/912; Y10S388/915; Y10S388/923; Y10S388/933
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
406 words
Apparatus for synchronizing and maintaining a measuring signal produced by a generator in phase with a reference signal comprising a control unit for controlling the generator, and a measuring circuit including a counter which has a first, a second, a third and a fourth count position, means for applying to the counter both the measuring signal and the reference signal each in the form of pulse trains so that the count in the counter is reduced one position by each measuring pulse and is increased one position by each reference pulse, the measuring circuit delivering a first output signal for controlling the control unit, said output signal having a first discrete value if the counter has reached the third or fourth position and a second discrete value if the counter has reached the first or second position, which first output signal from the measuring circuit so controls the control unit that it holds a control signal applied to the generator to a maximum value if the counter remains continuously in either of the positions three or four, or alternates between these positions, to a minimum value if the counter remains continuously in either of the positions one or two, or alternates between these positions, and to a value intermediate these minimum and maximum values and determined by the phase difference between successive measuring and reference pulses if the counter alternates between the second and third positions, characterized in that the control unit includes a sawtooth generator which supplies a sawtooth signal which is in synchronism with the reference signal and has the same frequency and the extreme values of which lie between the first and second discrete values and which varies in a direction which corresponds to the direction from the second discrete value to the first discrete value, and the control unit further includes a logic circuit having a first input and a second input to which the signal from the sawtooth generator and the first output signal from the measuring circuit are applied and which includes means for deriving an output signal that corresponds to the first discrete value if the first output signal from the measuring circuit has assumed said first discrete value, and to the value of the sawtooth signal if the first output signal from the measuring circuit has assumed the second discrete value, which output signal from the logic circuit may be used as the control signal for the generator.
Claim 2
Dependent Claim
406 words
Apparatus for synchronizing and maintaining a measuring signal produced by a generator in phase with a reference signal comprising a control unit for controlling the generator, and a measuring circuit including a counter which has a first, a second, a third and a fourth count position, means for applying to the counter both the measuring signal and the reference signal each in the form of pulse trains so that the count in the counter is reduced one position by each measuring pulse and is increased one position by each reference pulse, the measuring circuit delivering a first output signal for controlling the control unit, said output signal having a first discrete value if the counter has reached the third or fourth position and a second discrete value if the counter has reached the first or second position, which first output signal from the measuring circuit so controls the control unit that it holds a control signal applied to the generator to a maximum value if the counter remains continuously in either of the positions three or four, or alternates between these positions, to a minimum value if the counter remains continuously in either of the positions one or two, or alternates between these positions, and to a value intermediate these minimum and maximum values and determined by the phase difference between successive measuring and reference pulses if the counter alternates between the second and third positions, characterized in that the control unit includes a sawtooth generator which supplies a sawtooth signal which is in synchronism with the reference signal and has the same frequency and the extreme values of which lie between the first and second discrete values and which varies in a direction which corresponds to the direction from the second discrete value to the first discrete value, and the control unit further includes a logic circuit having a first input and a second input to which the signal from the sawtooth generator and the first output signal from the measuring circuit are applied and which includes means for deriving an output signal that corresponds to the first discrete value if the first output signal from the measuring circuit has assumed said first discrete value, and to the value of the sawtooth signal if the first output signal from the measuring circuit has assumed the second discrete value, which output signal from the logic circuit may be used as the control signal for the generator.
Claim 3
Dependent Claim
101 words
Apparatus as claimed in claim 1, characterized in that the logic circuit has a third input to which a second output signal from the measuring circuit is applied, which second output signal has a third discrete value if the counter is in the first position and a fourth discrete value if the counter is in any of the other positions, the sawtooth from the sawtooth generator lying between these third and fourth discrete values, and when the signal at the third input has the third discrete value the output signal from the logic circuit is clamped to said third discrete value.
Claim 4
Dependent Claim
60 words
Apparatus as claimed in claim 2, characterized in that the control unit includes a sampling circuit connected to receive the output signal from the logic circuit and which samples and measures the value of this signal at instants which correspond at least substantially to the occurence of the measuring pulses and holds each measured value until the next sampling instant.
Claim 5
Dependent Claim
41 words
Apparatus as claimed in claim 2 wherein the sawtooth generAtor is arranged to produce a sawtooth voltage that always commences with a value which corresponds to the third discrete value and terminates with a value equal to the first discrete value.
Claim 6
Dependent Claim
53 words
Apparatus as claimed in claim 1 for contolling the speed of a motor wherein the generator is coupled to the motor shaft and delivers a measuring signal the frequency of which is a measure of the motor speed, and means for applying the control signal to the motor for controlling the motor speed.
Claim 7
Dependent Claim
24 words
Apparatus as claimed in claim 1 wherein the generator comprises a voltage-controlled oscillator having a control input to which the control signal is applied.
Claim 8
Dependent Claim
38 words
Apparatus as claimed in claim 2 wherein, the logic circuit comprises the series connection of an OR gate and an AND gate which each have two input terminals which together form the three inputs of the logic circuit.
Claim 9
Dependent Claim
191 words
Signal synchronizing apparatus comprising, a source of reference pulses, a signal generator for producing a train of signal pulses to be locked in phase with said reference pulses, a reversible counter circuit having four count positions and first and second inputs for increasing and decreasing, respectively, the count in the counter, means for applying said reference pulses and said signal pulses to said counter first and second inputs, respectively, said counter circuit having an output circuit providing an output signal having a first value in the third or fourth positions of the counter and a second value in the first or second counter positions, and a control unit comprising, a sawtooth generator synchronized with the reference pulses and supplying a sawtooth signal of the reference pulse frequency having extreme amplitude values which lie between said first and second values and a logic circuit having first and second inputs coupled to receive the sawtooth signal and the counter output signal, respectively, and including means responsive to the sawtooth signal and output signal for deriving a control signal that is determined by the phase difference between the reference pulses and the signal pulses.
Claim 10
Dependent Claim
191 words
Signal synchronizing apparatus comprising, a source of reference pulses, a signal generator for producing a train of signal pulses to be locked in phase with said reference pulses, a reversible counter circuit having four count positions and first and second inputs for increasing and decreasing, respectively, the count in the counter, means for applying said reference pulses and said signal pulses to said counter first and second inputs, respectively, said counter circuit having an output circuit providing an output signal having a first value in the third or fourth positions of the counter and a second value in the first or second counter positions, and a control unit comprising, a sawtooth generator synchronized with the reference pulses and supplying a sawtooth signal of the reference pulse frequency having extreme amplitude values which lie between said first and second values and a logic circuit having first and second inputs coupled to receive the sawtooth signal and the counter output signal, respectively, and including means responsive to the sawtooth signal and output signal for deriving a control signal that is determined by the phase difference between the reference pulses and the signal pulses.
Claim 11
Dependent Claim
57 words
Apparatus as claimed in claim 8 wherein said logic circuit includes gating means for deriving a control signal of a fixed amplitude corresponding to said first value when the counter supplies an output signal of said first value and to the value of the sawtooth signal when the counter supplies an output signal of said second value.
Claim 12
Dependent Claim
51 words
Apparatus as claimed in claim 8 wherein the control unit further comprises a sample and hold circuit coupled to receive the signal output of the logic circuit and synchronized by the signal pulses to sample the logic circuit output signal at substantially those instants of time when the signal pulses occur.
Claim 13
Dependent Claim
31 words
Apparatus as claimed in claim 8 wherein said logic cicuit includes an OR gate having first and second inputs coupled to receive the sawtooth signal and the counter output signal, respectively.
Claim 14
Dependent Claim
101 words
Apparatus as claimed in claim 11 wherein the logic circuit further comprises an AND gate with one input coupled to the OR gate output and a second input coupled to a second output of the counter circuit which supplies a second output signal having a third value when the counter is in the first position and a fourth value when the counter is in the second, third or fourth positions, the output signal of the AND gate being clamped to said third value when the counter circuit supplies said third value output signal to the second input of the AND gate.
Claim 15
Dependent Claim
51 words
Apparatus as claimed in claim 12 wherein the control unit further comprises a sample and hold circuit coupled to receive the signal output of the AND gate and synchronized by the signal pulses to sample the AND gate output signal at substantially those instants of time when the signal pulses occur.
Claim 16
Dependent Claim
50 words
Apparatus as claimed in claim 8 for controlling the speed of a motor wherein the signal generator is controlled by the motor shaft to deliver signal pulses at a frequency determineD by the motor speed, and means for applying the control signal to the motor to control the speed thereof.
Claim 17
Dependent Claim
40 words
Apparatus as claimed in claim 8 wherein the signal generator comprises a voltage-controlled oscillator having a control input coupled to receive the control signal and an output circuit for supplying said signal pulses to the second input of the counter.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-27 | 1977-12-27 | 1978-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-27 | 1981-12-27 | 1982-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-27 | 1985-12-27 | 1986-06-28 | $7700.00 | Window Closed / Lapsed |