US3619804A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Frequency discriminator using an intermittently phase-locked loop
Assignee: Wilcox Electric Inc
•
Filing: 1969-01-23
•
Granted: 1971-11-09
•
Expires: 1989-01-23
Abstract
Abstract A frequency discriminator which compares a standard and an unknown frequency and generates a pulse output, the amplitude of which is proportional to the difference between the two frequencies. An amplitude sampling bridge is employed as a phase detector and is insensitive to harmonics, in that the standard frequency may be a subharmonic of the actual frequency with which the unknown frequency is to be compared. The standard frequency and the unknown frequency are delivered to the bridge in succession and individually compared with the output of an electrically controllable, variable frequency oscillator which is initially frequency-locked to the standard frequency, via a first control circuit and then via a second control circuit frequencylocked to the unknown frequency by the output pulse, the amplitude of that pulse being proportional to the frequency change of the oscillator output in proceeding from its first frequency-locked condition to its ultimate frequency.
Inventors
- 👤 William E Mears
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 12:36
CPC Classifications
H; H03; H03L; H03L7/00; H03L7/06; H03L7/08; H03L7/085; H03L7/091; G; G01; G01R; G01R23/00; G01R23/005; G01S; G01S11/00; G01S11/02; G01S11/10
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
270 words
A frequency discriminator comprising: a variable frequency oscillator for producing an oscillatory signal of controllable frequency; electrical phase detecting means; circuitry coupled with said detecting means for successively delivering thereto a first input signal of a standard frequency and a second input signal of an unknown frequency that may differ from a reference frequency, said standard and reference frequencies being the same or harmonically interrelated, said detecting means being coupled with said oscillator via a first frequency control circuit for comparing the phasing of said first input and controllable frequency signals and producing a first output signal representative of any detected phase difference, and for comparing via a second frequency control circuit the phasing of said second input and controllable frequency signals and producing a second output signal representative of the detected phase difference as said first and second input signals are successively delivered to the detecting means, said oscillator having two separate means separately responsive to said output signals for tuning the oscillator; and separate circuit means coupling the output of said detecting means with said two separate tuning means to complete frequency control loops and excite the tuning means with said first output signal to set the controllable frequency signal at an initial frequency, and to thereafter excite said tuning means with said second output signal to shift the frequency of said controllable frequency signal to a final frequency, said initial and standard frequencies being the same or harmonically interrelated and said final and unknown frequencies being the same or harmonically interrelated, whereby said second output signal is indicative of the difference between said reference and unknown frequencies.
Claim 2
Dependent Claim
270 words
A frequency discriminator comprising: a variable frequency oscillator for producing an oscillatory signal of controllable frequency; electrical phase detecting means; circuitry coupled with said detecting means for successively delivering thereto a first input signal of a standard frequency and a second input signal of an unknown frequency that may differ from a reference frequency, said standard and reference frequencies being the same or harmonically interrelated, said detecting means being coupled with said oscillator via a first frequency control circuit for comparing the phasing of said first input and controllable frequency signals and producing a first output signal representative of any detected phase difference, and for comparing via a second frequency control circuit the phasing of said second input and controllable frequency signals and producing a second output signal representative of the detected phase difference as said first and second input signals are successively delivered to the detecting means, said oscillator having two separate means separately responsive to said output signals for tuning the oscillator; and separate circuit means coupling the output of said detecting means with said two separate tuning means to complete frequency control loops and excite the tuning means with said first output signal to set the controllable frequency signal at an initial frequency, and to thereafter excite said tuning means with said second output signal to shift the frequency of said controllable frequency signal to a final frequency, said initial and standard frequencies being the same or harmonically interrelated and said final and unknown frequencies being the same or harmonically interrelated, whereby said second output signal is indicative of the difference between said reference and unknown frequencies.
Claim 3
Dependent Claim
73 words
The discriminator as claimed in claim 1, said circuitry including switching means for receiving said first and second input signals and normally effecting delivery of only said first input signal to said detecting means, and control means coupled with said switching means for operating the latter for a predetermined time period to effect delivery of said second input signal to said detecting means and terminate the delivery of said first input signal thereTo.
Claim 4
Dependent Claim
68 words
The discriminator as claimed in claim 1, said detecting means including means for sampling the amplitude of said first or said second input signals at predetermined times during each period of said controllable frequency signal as said first and second input signals are successively delivered to the detecting means, and output means responsive to said amplitude sampling for effecting production of the corresponding first or second output signal.
Claim 5
Dependent Claim
110 words
The discriminator as claimed in claim 3, said sampling means including a normally nonconductive, amplitude sampling bridge for receiving said first and second input signals, means responsive to said controllable frequency signal for delivering a sampling pulse to said bridge at said predetermined time to render the bridge momentarily conductive and effect said amplitude sampling, and energy storage means operably coupled with said bridge for receiving energy during said momentary conduction and developing a voltage in accordance with the phase difference of the signals under comparison, said output means including an amplifier coupled with said energy storage means for deriving the corresponding first or second output signal from said voltage.
Claim 6
Dependent Claim
61 words
The discriminator as claimed in claim 1, said oscillator including a tank circuit having first and second electrically controllable, variable reactance tuning circuits coupled to said tank circuit as said means for tuning the oscillator, said circuit means delivering said first output signal exclusively to said first tuning circuit, and delivering said second output signal exclusively to said second tuning circuit.
Claim 7
Dependent Claim
47 words
The discriminator as claimed in claim 5, there being means coupled with said first tuning circuit for holding the latter at the reactance previously required to set the controllable frequency signal at the initial frequency, during delivery of said second output signal to said second tuning circuit.
Claim 8
Dependent Claim
36 words
The discriminator as claimed in claim 6, there being means coupled with said second tuning circuit for returning the latter to a constant value of reactance upon termination of delivery of said second output signal thereto.
Claim 9
Dependent Claim
149 words
The discriminator as claimed in claim 1, said tuning means including a tank having first and second electrically controllable, variable reactance tuning circuits, said circuit means having first switching means for controlling delivery of said output signals to said tuning circuits and normally establishing electrical continuity only between the output of said detecting means and said first tuning circuit, said circuitry including second switching means for receiving said input signals and normally effecting delivery of only said first input signal to said detecting means, and control means coupled with said first and second switching means for operating the latter for a predetermined time period to effect delivery of said second input signal to said detecting means, terminate the delivery of said first input signal thereto, interrupt said continuity to said first tuning circuit, and establish electrical continuity between the output of said detecting means and said second tuning circuit.
Claim 10
Dependent Claim
63 words
The discriminator as claimed in claim 8, there being means coupled with said first tuning circuit for holding the latter, during said predetermined time period, at the reactance previously required to set the controllable frequency signal at the initial frequency; and means coupled with said second tuning circuit for returning the latter to a constant value of reactance following said predetermined time period.
Claim 11
Dependent Claim
134 words
The discriminator as claimed in claim 1, said tuning means including a tank having a reactive element and an electrically controllable, variable reactance tuning circuit capable of resonating with said element, said tuning circuit comprising a field effect transistor having source and drain connections and a gate, means coupled with said field Effect transistor for applying operating potential thereto, means coupled with said field effect transistor for establishing a substantially 90* phase difference between current flowing through said source and drain connections and the voltage across said connections, means coupling said field effect transistor with said element to cause said current to interact with said element to establish a resonant frequency, and means for receiving one of said output signals and applying the same to said gate to control the magnitude of said current.
Claim 12
Dependent Claim
181 words
In a frequency discriminator; a phase-locked loop including a phase detector, an oscillator connected to said phase detector to provide an input signal thereto, a source of reference signal of standard frequency, a source of unknown frequency, a reactance circuit connectable to said oscillator for tuning said oscillator, a zero set tuning circuit connectable to said oscillator for tuning said oscillator, said zero set tuning circuit being in addition to said reactance circuit, means normally applying said reference signal to said phase detector while maintaining said zero set tuning circuit responsive to the phase-detected output of said phase detector, whereby said oscillator is tuned to a harmonic of said reference frequency by said zero set tuning circuit, a hold circuit for maintaining the zero set tuning circuit at its latest tuning setting despite interruption of said reference frequency, and means for at intervals interrupting said reference frequency and applying said signal of unknown frequency to said phase detector and the phase-detected output of said phase detector to said reactance circuit while said hold circuit maintains the zero set of said oscillator.
Claim 13
Dependent Claim
181 words
In a frequency discriminator; a phase-locked loop including a phase detector, an oscillator connected to said phase detector to provide an input signal thereto, a source of reference signal of standard frequency, a source of unknown frequency, a reactance circuit connectable to said oscillator for tuning said oscillator, a zero set tuning circuit connectable to said oscillator for tuning said oscillator, said zero set tuning circuit being in addition to said reactance circuit, means normally applying said reference signal to said phase detector while maintaining said zero set tuning circuit responsive to the phase-detected output of said phase detector, whereby said oscillator is tuned to a harmonic of said reference frequency by said zero set tuning circuit, a hold circuit for maintaining the zero set tuning circuit at its latest tuning setting despite interruption of said reference frequency, and means for at intervals interrupting said reference frequency and applying said signal of unknown frequency to said phase detector and the phase-detected output of said phase detector to said reactance circuit while said hold circuit maintains the zero set of said oscillator.
Claim 14
Independent Claim
164 words
A system for measuring the divergence of the frequency of a first signal from a standard frequency provided by a source of a standard signal, comprising: a phase-locked loop including a phase detector having alternative input circuits for said signals and a further input circuit, a frequency controllable oscillator providing a signal to said further input circuit, a zero set frequency control circuit means arranged to be responsive to the output of said phase detector for maintaining a frequency correspondence between the frequency of said oscillator and the frequency of said source of a standard signal, said zero set frequency control circuit including means for maintaining the frequency setting of said zero set frequency control circuit means for a period immediately following a disconnection of said source of a standard signal from said phase detector, and a further frequency control circuit connectable to said oscillator with application to said phase detector of said first signal and disconnection of said source of a standard frequency.
Claim 15
Independent Claim
164 words
A system for measuring the divergence of the frequency of a first signal from a standard frequency provided by a source of a standard signal, comprising: a phase-locked loop including a phase detector having alternative input circuits for said signals and a further input circuit, a frequency controllable oscillator providing a signal to said further input circuit, a zero set frequency control circuit means arranged to be responsive to the output of said phase detector for maintaining a frequency correspondence between the frequency of said oscillator and the frequency of said source of a standard signal, said zero set frequency control circuit including means for maintaining the frequency setting of said zero set frequency control circuit means for a period immediately following a disconnection of said source of a standard signal from said phase detector, and a further frequency control circuit connectable to said oscillator with application to said phase detector of said first signal and disconnection of said source of a standard frequency.
Claim 16
Dependent Claim
139 words
A frequency control system, comprising: an oscillator having a zero set tuner, a source of reference signal of known frequency, a source of further signal of unknown frequency, a phase detector, first frequency control means responsive to said reference signal for controlling said phase detector to set the frequency of said oscillator via said zero set tuner into predetermined frequency relation to the frequency of said reference signal and to maintain the setting of said zero set tuner following a termination of application of said reference signal to said phase detector, second frequency control means responsive to said further signal for controlling said phase detector to modify the frequency of said oscillator into predetermined frequency relation to the frequency of said further signal, and means applying said reference signal and further signal to said phase detector in time sequence.
Claim 17
Dependent Claim
139 words
A frequency control system, comprising: an oscillator having a zero set tuner, a source of reference signal of known frequency, a source of further signal of unknown frequency, a phase detector, first frequency control means responsive to said reference signal for controlling said phase detector to set the frequency of said oscillator via said zero set tuner into predetermined frequency relation to the frequency of said reference signal and to maintain the setting of said zero set tuner following a termination of application of said reference signal to said phase detector, second frequency control means responsive to said further signal for controlling said phase detector to modify the frequency of said oscillator into predetermined frequency relation to the frequency of said further signal, and means applying said reference signal and further signal to said phase detector in time sequence.
Claim 18
Dependent Claim
257 words
In a system for measuring the frequency differences between a frequency of a signal of fixed reference frequencies constituting harmonics and the frequency of a signal of a randomly variable fRequency, a phase-locked loop including a phase detector, a variable frequency oscillator having a zero set tuner, said phase-locked loop including said zero set tuner and oscillator and said phase detector connected in series in the recited order, a source of signal at said reference frequency, means transiently applying said signal of reference frequency and permanently applying the output of said oscillator to said phase detector as inputs to be compared as to frequency by said phase detector, first frequency control means applying the output of said phase detector to control the frequency of said variable frequency oscillator in such sense as to equalize frequency of said oscillator and one of said harmonics of the frequency of said signal of fixed reference frequency and for thereafter for a period of time after disconnection of said signal of fixed reference frequency from said phase detector maintaining fixed said zero set tuner, a second frequency control means for transiently applying said signal of randomly varying frequency to said phase detector with substitution of said signal at said reference frequency and applying the output of said phase detector to further control the frequency of said variable frequency oscillator via said second frequency control means during said period of time in such sense as to equalize the frequencies of said oscillator and the frequency of said signal of randomly varying frequency.
Claim 19
Dependent Claim
257 words
In a system for measuring the frequency differences between a frequency of a signal of fixed reference frequencies constituting harmonics and the frequency of a signal of a randomly variable fRequency, a phase-locked loop including a phase detector, a variable frequency oscillator having a zero set tuner, said phase-locked loop including said zero set tuner and oscillator and said phase detector connected in series in the recited order, a source of signal at said reference frequency, means transiently applying said signal of reference frequency and permanently applying the output of said oscillator to said phase detector as inputs to be compared as to frequency by said phase detector, first frequency control means applying the output of said phase detector to control the frequency of said variable frequency oscillator in such sense as to equalize frequency of said oscillator and one of said harmonics of the frequency of said signal of fixed reference frequency and for thereafter for a period of time after disconnection of said signal of fixed reference frequency from said phase detector maintaining fixed said zero set tuner, a second frequency control means for transiently applying said signal of randomly varying frequency to said phase detector with substitution of said signal at said reference frequency and applying the output of said phase detector to further control the frequency of said variable frequency oscillator via said second frequency control means during said period of time in such sense as to equalize the frequencies of said oscillator and the frequency of said signal of randomly varying frequency.
Claim 20
Independent Claim
102 words
The method of measuring the difference of frequency between a fixed frequency and a variable frequency, comprising: voltage controlling the frequency of an oscillator to have a correspondence with said fixed frequency by adjusting a first frequency control circuit for said oscillator and thereafter maintaining the adjustment of said first frequency control circuit for a time period and thereafter and during said time period further voltage controlling the frequency of said oscillator to have correspondence with said variable frequency by adjusting a second frequency control circuit for said oscillator, and indicating the latter voltage as a measure of the difference of frequency.
Claim 21
Independent Claim
102 words
The method of measuring the difference of frequency between a fixed frequency and a variable frequency, comprising: voltage controlling the frequency of an oscillator to have a correspondence with said fixed frequency by adjusting a first frequency control circuit for said oscillator and thereafter maintaining the adjustment of said first frequency control circuit for a time period and thereafter and during said time period further voltage controlling the frequency of said oscillator to have correspondence with said variable frequency by adjusting a second frequency control circuit for said oscillator, and indicating the latter voltage as a measure of the difference of frequency.
Claim 22
Dependent Claim
188 words
A frequency comparison system, comprising: a first source of signal of unknown frequency, a second source of signal of standard frequency, a selective switch arranged to select said signals alternatively to an output lead, an oscillator, two reactance tuning circuits coupled to said oscillator for separately controlling the frequency of said oscillator, a phase detector having inputs connected to said output lead of said selective switch and to an output of said oscillator, respectively, and having an output connected in cascade with said oscillator, an off-on switch, a feedback lead extending in cascade with said phase detector, a sample-and-hold zero set circuit including one of said two reactance tuning circuits connected between said feedback lead and said oscillator, a circuit connecting said lead via said off-on switch to the other of said reactance circuits, and means for in alternation turning said off-on switch off and activating said sample-and-hold zero set circuit and activating said selective switch to said signal of standard frequency and thereafter turning on said off-on switch and deactivating said sample-and-hold zero set circuit and controlling said selective switch to select said signal of unknown frequency.
Claim 23
Dependent Claim
188 words
A frequency comparison system, comprising: a first source of signal of unknown frequency, a second source of signal of standard frequency, a selective switch arranged to select said signals alternatively to an output lead, an oscillator, two reactance tuning circuits coupled to said oscillator for separately controlling the frequency of said oscillator, a phase detector having inputs connected to said output lead of said selective switch and to an output of said oscillator, respectively, and having an output connected in cascade with said oscillator, an off-on switch, a feedback lead extending in cascade with said phase detector, a sample-and-hold zero set circuit including one of said two reactance tuning circuits connected between said feedback lead and said oscillator, a circuit connecting said lead via said off-on switch to the other of said reactance circuits, and means for in alternation turning said off-on switch off and activating said sample-and-hold zero set circuit and activating said selective switch to said signal of standard frequency and thereafter turning on said off-on switch and deactivating said sample-and-hold zero set circuit and controlling said selective switch to select said signal of unknown frequency.
Claim 24
Dependent Claim
16 words
The combination according to claim 16 wherein said phase detector is an amplitude sampling bridge circuit.
Claim 25
Dependent Claim
61 words
The combination according to claim 17, wherein said phase detector includes means for coupling output of said oscillator at crossover points of said output to develop sampling pulses at said crossover points, and means responsive to said sampling pulses for selectively sampling said signal of unknown frequency and said signal of standard frequency according to the condition of said selective switch.
Claim 26
Dependent Claim
54 words
The combination accoRding to claim 18, wherein said sample hold and zero set circuit includes a varactor diode connected to control the frequency of said oscillator and a storage capacitor connected to impart its voltage to said varactor diode, and means charging said storage capacitor in response to the output of said phase detector.
Claim 27
Dependent Claim
171 words
In a frequency measuring system, a source of signal at reference frequency, a source of signal of unknown frequency, an oscillator, a first voltage-controlled tuner for said oscillator, a second voltage-controlled tuner for said oscillator, a storage capacitor so coupled to said first voltage-controlled tuner that the voltage across said storage capacitor provides the control voltage for said first voltage-controlled tuner, first means responsive to the frequency of said signal at reference frequency for applying a first voltage across said storage capacitor such as to maintain the frequency of said oscillator in predetermined frequency relation to said reference frequency, second means operative only subsequent to operation of said first means and responsive to said signal of unknown frequency to apply to said second voltage-controlled tuner a further control voltage designed to produce a predetermined frequency relation between the frequency of said oscillator and said unknown frequency while said storage capacitor maintains its voltage, whereby said further control voltage is representative of the difference between said unknown frequency and said reference frequency.
Claim 28
Dependent Claim
171 words
In a frequency measuring system, a source of signal at reference frequency, a source of signal of unknown frequency, an oscillator, a first voltage-controlled tuner for said oscillator, a second voltage-controlled tuner for said oscillator, a storage capacitor so coupled to said first voltage-controlled tuner that the voltage across said storage capacitor provides the control voltage for said first voltage-controlled tuner, first means responsive to the frequency of said signal at reference frequency for applying a first voltage across said storage capacitor such as to maintain the frequency of said oscillator in predetermined frequency relation to said reference frequency, second means operative only subsequent to operation of said first means and responsive to said signal of unknown frequency to apply to said second voltage-controlled tuner a further control voltage designed to produce a predetermined frequency relation between the frequency of said oscillator and said unknown frequency while said storage capacitor maintains its voltage, whereby said further control voltage is representative of the difference between said unknown frequency and said reference frequency.
Claim 29
Dependent Claim
15 words
The combination according to claim 20, wherein said first voltage-controlled tuner is a diode varactor.
Claim 30
Dependent Claim
15 words
The combination according to claim 21, wherein said second voltage-controlled tuner is a variable reactance.
Claim 31
Dependent Claim
15 words
The combination according to claim 22, wherein said oscillator is incorporated in a phase-locked loop.
Claim 32
Dependent Claim
65 words
The combination according to claim 23, wherein said phase-locked loop includes a phase detector of the amplitude sampling type responsive jointly to the output of said oscillator and in alternation to said signal of reference frequency and to said signal of unknown frequency, and means for directing the output of said phase detector in corresponding alternation to said diode varactor and to said variable reactance.
Claim 33
Dependent Claim
106 words
In a system for measuring the difference in frequency between a standard frequency and a further frequency, an oscillator, a first tuner for said oscillator, a second control signal-controlled tuner for said oscillator, means for achieving and maintaining a setting of said first tuner which tunes said oscillator to said standard frequency, and means operative while said first tuner maintains said setting for applying a control signal to said control signal-controlled tuner of such value that the frequency of said oscillator varies into equality with said further frequency, and means for measuring the variation of said value of said control signal required to achieve said equality.
Claim 34
Dependent Claim
106 words
In a system for measuring the difference in frequency between a standard frequency and a further frequency, an oscillator, a first tuner for said oscillator, a second control signal-controlled tuner for said oscillator, means for achieving and maintaining a setting of said first tuner which tunes said oscillator to said standard frequency, and means operative while said first tuner maintains said setting for applying a control signal to said control signal-controlled tuner of such value that the frequency of said oscillator varies into equality with said further frequency, and means for measuring the variation of said value of said control signal required to achieve said equality.
Claim 35
Dependent Claim
35 words
The combination according to claim 25, wherein is provided a phase-locked loop phase detector, each of said first tuner and said second tuner being separately responsive to said phase detector at discrete times in alternation.
References Cited (Backward Citations)
US3059187A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-08 | 1975-05-10 | 1975-11-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-08 | 1979-05-10 | 1979-11-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-08 | 1983-05-10 | 1983-11-09 | $7700.00 | Window Closed / Lapsed |