Patent US3916307A successfully refreshed from Google Patents.
US3916307A
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Time jitter meter
Assignee: Hekimian Laboratories Inc
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Filing: 1974-02-14
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Granted: 1975-10-28
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Expires: 1994-02-14
Abstract
Abstract A time jitter meter is capable of receiving pulse trains at a variety of repetition rates and measuring pulse transition time jitter with a variety of resolution capabilities. The pulse train and its associated jitter are translated to a first standard intermediate frequency which is passed through a narrowband IF filter. The filtered signal is passed through a zero-crossing limiter and then frequency-divided by a selected divider to determine measurement resolution. The frequency-divided signal is then translated to a second standard intermediate frequency which is applied to a phase lock loop in which it is compared against the phase of a VCO. Phase excursions detected in the loop are measured on an RMS meter and a phase hit counter. The loop employs a unique integrator which permits rapid phase lock followed by smooth tracking of the input signal. The integrator is operated as an amplifier prior to phase lock, the integrating capacitor being permitted to charge to the amplifier output level while remaining outside the loop. When phase lock occurs the charged capacitor is switched into the loop at the proper charge level. The loop thus changes smoothly from a wide band first order loop before phase lock to a narrowband second order loop after phase lock.
Inventors
- 👤 Norris C Hekimian
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 13:17
CPC Classifications
H; H03; H03K; H03K5/00; H03K5/00006; H03K9/00; H03K9/06; H03L; H03L7/00; H03L7/06; H03L7/08; H03L7/10; H03L7/107; H03L7/1075; Y; Y10; Y10S; Y10S331/00; Y10S331/02
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
170 words
A time jitter meter for measuring time jitter on a plurality of individually applied input pulse trains of different frequency, said time jitter meter comprising: a phase lock loop arranged to receive a measurement signal exhibiting time jitter to be measured, said loop comprising: a voltage controlled oscillator for providing a VCO signal at a nominal frequency; phase detector means for providing an error signal having an amplitude which is a function of the phase displacement between said measurement signal and said VCO signal; and integrator means for time-averaging said error signal and controlling the phase of said voltage controlled oscillator in accordance with the time-averaged value of the error signal amplitude; signal conditioner means for receiving said individually applied input pulse trains and converting each received pulse train to said measurement signal having said nominal frequency and bearing the same time jitter as the converted input pulse train; and measurement means responsive to said error signal for providing an indication of at least one parameter of said error signal.
Claim 2
Dependent Claim
170 words
A time jitter meter for measuring time jitter on a plurality of individually applied input pulse trains of different frequency, said time jitter meter comprising: a phase lock loop arranged to receive a measurement signal exhibiting time jitter to be measured, said loop comprising: a voltage controlled oscillator for providing a VCO signal at a nominal frequency; phase detector means for providing an error signal having an amplitude which is a function of the phase displacement between said measurement signal and said VCO signal; and integrator means for time-averaging said error signal and controlling the phase of said voltage controlled oscillator in accordance with the time-averaged value of the error signal amplitude; signal conditioner means for receiving said individually applied input pulse trains and converting each received pulse train to said measurement signal having said nominal frequency and bearing the same time jitter as the converted input pulse train; and measurement means responsive to said error signal for providing an indication of at least one parameter of said error signal.
Claim 3
Dependent Claim
78 words
The time jitter meter according to claim 1 wherein said signal conditioner means comprises: first translation means for converting the applied pulse train to an intermediate signal having a predetermined frequency and bearing the same time jitter as said applied pulse train; resolution control means for selectively dividing the frequency of said intermediate signal by one of plural operator-selectable factors; and second translation means for converting the frequency-divided intermediate signal to said measurement signal at said nominal frequency.
Claim 4
Dependent Claim
182 words
The time jitter meter according to claim 2 wherein said first translation means comprises: a plurality of local oscillators, one for each of said plurality of input pulse trains, the frequency of each local oscillator being such that the sum of or the difference between that local oscillator frequency and a respective input pulse train frequency equals said predetermined frequency of said intermediate signal; mixer means for mixing two signals applied thereto and providing signal components at the sum and difference frequencies of the two applied signals; means for applying the input pulse train to said mixer means as one of said two signals; means for selectively applying to said mixer means, as the second of said two signals, a signal from the local oscillator having a frequency which when added to or subtracted from said predetermined frequency is equal to the frequency of said input pulse train; and bandpass filter means tuned to said predetermined frequency for receiving the signal components provided by said mixing means and passing as said intermediate signal only that frequency component equal to said predetermined frequency.
Claim 5
Dependent Claim
98 words
The time jitter meter according to claim 3 wherein said phase lock loop further comprises: phase lock detector means responsive to said measurement signal and said VCO signal for providing a control signal indicating when the voltage controlled oscillator is not phase locked to the meAsurement signal; means responsive to said control signal for charging said integrator means outside of said phase lock loop when said VCO signal is not phase locked to the measurement signal, and for charging said integrator means within said phase lock loop when said VCO signal is in phase with said measurement signal.
Claim 6
Dependent Claim
134 words
The time jitter meter according to claim 3 wherein said integrator means includes a capacitor and an operational amplifier having an input terminal and an output terminal, said output terminal being connected to one side of said capacitor, and wherein said phase lock loop further comprises: phase lock detector means responsive to said measurement signal and said VCO signal for providing a control signal when the VCO signal is not phase locked to the measurement signal; and switch means responsive to said control signal for connecting the other side of said capacitor to ground when said VCO signal is not phase locked to said measurement signal and for connecting said other side of said capacitor to the input terminal of said operational amplifier when said VCO signal is phase locked to said measurement signal.
Claim 7
Dependent Claim
49 words
The time jitter meter according to claim 5 wherein said measurement means comprises: hit detector means responsive to each excursion of the amplitude of said error signal above a pre-established level for providing a hit pulse; and hit counter means for counting hit pulses from said hit detector means.
Claim 8
Dependent Claim
28 words
The time jitter meter according to claim 6 further comprising settable timer means for limiting counting of said hit pulses at said hit counter to selectable time intervals.
Claim 9
Dependent Claim
29 words
The time jitter meter according to claim 5, wherein said measurement means comprises: meter circuit means for providing an RMS meter indication of the amplitude of said error signal.
Claim 10
Dependent Claim
49 words
The time jitter meter according to claim 2, wherein said measurement means comprises: hit detector means responsive to each excursion of the amplitude of said error signal above a pre-established level for providing a hit pulse; and hit counter means for counting hit pulses from said hit detector means.
Claim 11
Dependent Claim
29 words
The time jitter meter according to claim 2 wherein said measurement means comprises: meter circuit means for providing an RMS meter indication of the amplitude of said error signal.
Claim 12
Dependent Claim
98 words
The time jitter meter according to claim 1 wherein said phase lock loop further comprises: phase lock detector means responsive to said measurement signal and said VCO signal for providing a control signal indicating when the voltage controlled oscillator is not phase locked to the measurement signal; means responsive to said control signal for charging said integrator means outside of said phase lock loop when said VCO signal is not phase locked to the measurement signal, and for charging said integrator means within said phase lock loop when said VCO signal is in phase with said measurement signal.
Claim 13
Dependent Claim
134 words
The time jitter meter according to claim 1 wherein said integrator means includes a capacitor and an operational amplifier having an input terminal and an output terminal, said output terminal being connected to one side of said capacitor, and wherein said phase lock loop further comprises: phase lock detector means responsive to said measurement signal and said VCO signal for providing a control signal when the VCO signal is not phase locked to the measurement signal; and switch means responsive to said control signal for connecting the other side of said capacitor to ground when said VCO signal is not phase locked to said measurement signal and for connecting said other side of said capacitor to the input terminal of said operational amplifier when said VCO signal is phase locked to said measurement signal.
Claim 14
Independent Claim
135 words
A method for measuring time jitter on a plurality of individually applied input pulse trains of different frequency, said method comprising the steps of: processinG a measurement signal exhibiting time jitter to be measured by the steps of: providing a VCO signal having a nominal frequency which is voltage responsive; providing an error signal having an amplitude which is a function of the phase displacement between said measurement signal and said VCO signal; time-averaging said error signal; and controlling the phase of said voltage controlled oscillator in accordance with the time-averaged value of the error signal amplitude; converting each of said individually applied input pulse trains to said measurement signal at said nominal frequency and bearing the same time jitter as the converted input pulse train; and measuring a predetermined parameter of said error signal.
Claim 15
Independent Claim
135 words
A method for measuring time jitter on a plurality of individually applied input pulse trains of different frequency, said method comprising the steps of: processinG a measurement signal exhibiting time jitter to be measured by the steps of: providing a VCO signal having a nominal frequency which is voltage responsive; providing an error signal having an amplitude which is a function of the phase displacement between said measurement signal and said VCO signal; time-averaging said error signal; and controlling the phase of said voltage controlled oscillator in accordance with the time-averaged value of the error signal amplitude; converting each of said individually applied input pulse trains to said measurement signal at said nominal frequency and bearing the same time jitter as the converted input pulse train; and measuring a predetermined parameter of said error signal.
Claim 16
Dependent Claim
69 words
The time jitter meter according to claim 13 wherein said step of converting includes the steps of: converting the applied pulse train to an intermediate signal having a predetermined frequency and bearing the same time jitter as said applied pulse train; selectively dividing the frequency of said intermediate signal by one of plural operator-selectable factors; and converting the frequency-divided intermediate signal to said measurement signal at said nominal frequency.
Claim 17
Dependent Claim
78 words
The time jitter meter according to claim 14 wherein said step of processing includes the steps of: providing a control signal indicating when the voltage controlled oscillator is not phase locked to the measurement signal; charging said integrator means outside of said phase lock loop when said VCO signal is not phase locked to the measurement signal; and charging said integrator means within said phase lock loop when said VCO signal is in phase with said measurement signal.
References Cited (Backward Citations)
US3711773A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-27 | 1979-04-28 | 1979-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-27 | 1983-04-28 | 1983-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-27 | 1987-04-28 | 1987-10-28 | $7700.00 | Window Closed / Lapsed |