US3737766A
Expired / Lapsed
US
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Testing technique for phase jitter in communication systems
Assignee: SPX Technologies Inc
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Filing: 1971-12-06
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Granted: 1973-06-05
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Expires: 1991-12-06
Abstract
Abstract A method and apparatus for measuring phase jitter by monitoring the period of a communication signal output of a communication system each one-half cycle. At each one-half cycle, the width of the signal output is compared with an average one-half period of the signal. Both digital and analog techniques are disclosed for displaying a peak-per-cycle phase jitter and a cumulative peakto-peak phase jitter of the signal.
Inventors
- 👤 A Lubarsky
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 10:26
CPC Classifications
H; H04; H04L; H04L1/00; H04L1/20; H04L1/205
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
108 words
A method of testing a communication circuit for phase jitter, comprising the steps of: inserting a test signal into an input of said communication circuit, measuring the duration of each one-half cycle of the test signal at an output of the communication circuit, determining an average one-half cycle duration of the signal at the output of said communication circuit and, comparing each one-half cycle duration with said average onehalf cycle duration to determine differences therebetween, whereby the differences between the one-half cycle durations of the test signal output and the average one-half cycle duration indicate phase jitter of the test signal at the output of the communication circuit.
Claim 2
Independent Claim
108 words
A method of testing a communication circuit for phase jitter, comprising the steps of: inserting a test signal into an input of said communication circuit, measuring the duration of each one-half cycle of the test signal at an output of the communication circuit, determining an average one-half cycle duration of the signal at the output of said communication circuit and, comparing each one-half cycle duration with said average onehalf cycle duration to determine differences therebetween, whereby the differences between the one-half cycle durations of the test signal output and the average one-half cycle duration indicate phase jitter of the test signal at the output of the communication circuit.
Claim 3
Independent Claim
86 words
A method of measuring a disturbance in the periodicity of zero crossings of a test signal, comprising the steps of: measuring the duration of each one-half cycle of the test signal, determining an average one-half cycle duration of the test signal, comparing each one-half cycle duration with said average one-half cycle duration to determine differeces therebetween, and expressing the individual differences between the one-half cycle durations of the test signal and the average one-half cycle duration in terms of degress of said average one-half cycle duration.
Claim 4
Independent Claim
86 words
A method of measuring a disturbance in the periodicity of zero crossings of a test signal, comprising the steps of: measuring the duration of each one-half cycle of the test signal, determining an average one-half cycle duration of the test signal, comparing each one-half cycle duration with said average one-half cycle duration to determine differeces therebetween, and expressing the individual differences between the one-half cycle durations of the test signal and the average one-half cycle duration in terms of degress of said average one-half cycle duration.
Claim 5
Independent Claim
96 words
A method of measuring a disturbance in the periodicity of zero crossings of a test signal, comprising the steps of: measuring the duration of each one-half cycle of the test signal, determining an average one-half cycle duRation of the test signal, comparing each one-half cycle duration with said average one-half cycle duration to determine differences there-between, and identifying and measuring the peak difference between the one-half cycle durations of the test signal and the average one-half cycle duration, whereby said peak difference over a predetermined period of time is a useful indication of per-cycle peak jitter.
Claim 6
Independent Claim
96 words
A method of measuring a disturbance in the periodicity of zero crossings of a test signal, comprising the steps of: measuring the duration of each one-half cycle of the test signal, determining an average one-half cycle duRation of the test signal, comparing each one-half cycle duration with said average one-half cycle duration to determine differences there-between, and identifying and measuring the peak difference between the one-half cycle durations of the test signal and the average one-half cycle duration, whereby said peak difference over a predetermined period of time is a useful indication of per-cycle peak jitter.
Claim 7
Independent Claim
129 words
A method of measuring a disturbance in the periodicity of zero crossings of a test signal, comprising the steps of: measuring the duration of each one-half cycle of the test signal, determining an average one-half cycle duration of the test signal, comparing each one-half cycle duration with said average one-half cycle duration to determine differences therebetween, totalling said differences in a manner that the one-half cycles of the test signal that are greater in duration than the average one-half cycle duration are given one sign while the differences arising from the one-half cycles of the test signal that are less in duration than the average one-half cycle period are given an opposite sign, and observing said total, whereby said total is a useful indication of total peak-to-peak phase jitter.
Claim 8
Independent Claim
129 words
A method of measuring a disturbance in the periodicity of zero crossings of a test signal, comprising the steps of: measuring the duration of each one-half cycle of the test signal, determining an average one-half cycle duration of the test signal, comparing each one-half cycle duration with said average one-half cycle duration to determine differences therebetween, totalling said differences in a manner that the one-half cycles of the test signal that are greater in duration than the average one-half cycle duration are given one sign while the differences arising from the one-half cycles of the test signal that are less in duration than the average one-half cycle period are given an opposite sign, and observing said total, whereby said total is a useful indication of total peak-to-peak phase jitter.
Claim 9
Independent Claim
263 words
A method of observing phase jitter in an electrical signal, comprising the steps of: deriving from said electrical signal a square wave signal having alternative high level and low level values with a frequency that follows that of said electrical signal. keying a first pulse generator coincident in time with a rising edge of each square wave cycle, thereby to generate a pulse simultaneous with each positive one-half cycle of the square wave, keying a second pulse generator coincident in time with the descending edge of each square wave cycle, thereby to generate a pulse simultaneous with each negative one-half cycle of the square wave, comparing the duration of each pulse generated by the first pulse generator with the duration of its simultaneous positive one-half cycle of the square wave signal and generating a differential pulse having a duration proportional to the difference in duration therebetween, comparing the duration of each pulse generated by the second pulse generator means with the duration of its simultaneous negative one-half cycle of the square wave signal and generating a differential pulse having a duration proportional to the difference therebetween, integrating the positive one-half cycle differential pulses and applying the integrated value of said first pulse generator to control the duration of the pulses generated thereby; integrating the negative one-half cycle differential pulses and applying the integrated value to said second pulse generator to control the duration of the pulses generated thereby, whereby the duration of said differential pulses is indicative of per cycle phase differences in the electrical signal with respect to an average period thereof.
Claim 10
Independent Claim
263 words
A method of observing phase jitter in an electrical signal, comprising the steps of: deriving from said electrical signal a square wave signal having alternative high level and low level values with a frequency that follows that of said electrical signal. keying a first pulse generator coincident in time with a rising edge of each square wave cycle, thereby to generate a pulse simultaneous with each positive one-half cycle of the square wave, keying a second pulse generator coincident in time with the descending edge of each square wave cycle, thereby to generate a pulse simultaneous with each negative one-half cycle of the square wave, comparing the duration of each pulse generated by the first pulse generator with the duration of its simultaneous positive one-half cycle of the square wave signal and generating a differential pulse having a duration proportional to the difference in duration therebetween, comparing the duration of each pulse generated by the second pulse generator means with the duration of its simultaneous negative one-half cycle of the square wave signal and generating a differential pulse having a duration proportional to the difference therebetween, integrating the positive one-half cycle differential pulses and applying the integrated value of said first pulse generator to control the duration of the pulses generated thereby; integrating the negative one-half cycle differential pulses and applying the integrated value to said second pulse generator to control the duration of the pulses generated thereby, whereby the duration of said differential pulses is indicative of per cycle phase differences in the electrical signal with respect to an average period thereof.
Claim 11
Dependent Claim
122 words
A phase jitter test apparatus, comprising means responsive to a test signal for generating a pulse concurrently with each positive one-half cycle of said signal, each of said pulses having a duration equal to the difference between the duration of one positive half cycle and one-half an average period of said test signal, means responsive to said test signal for generating a pulse concurrently with each negative one-half cycle of said signal, each of said pulses having a duration equal to the difference between the duration of one negative half cycle and one-half the average period of said test signal, and means measuring the width of each of said generated difference pulses in degrees of the average period of said test signal.
Claim 12
Dependent Claim
122 words
A phase jitter test apparatus, comprising means responsive to a test signal for generating a pulse concurrently with each positive one-half cycle of said signal, each of said pulses having a duration equal to the difference between the duration of one positive half cycle and one-half an average period of said test signal, means responsive to said test signal for generating a pulse concurrently with each negative one-half cycle of said signal, each of said pulses having a duration equal to the difference between the duration of one negative half cycle and one-half the average period of said test signal, and means measuring the width of each of said generated difference pulses in degrees of the average period of said test signal.
Claim 13
Dependent Claim
30 words
Apparatus according to claim 6 which additionally comprises: means for selecting from the difference pulses generated during a predetermined length of time the one pulse that has a maximum width.
Claim 14
Dependent Claim
92 words
Apparatus according to claim 6 wherein said means for Generating a pulse concurrently with each positive one-half cycle and said means for generating a pulse concurrently with each negative one-half cycle each include a phase lock loop comprising, a one-shot multivibrator that is triggered by the test signal, an edge comparator receiving the multivibrator output and comparing it to the corresponding test signal one-half cycles, thereby to develop said pulses, and a differential integrator receiving said pulses, the output of the integrator being fed back to said multivibrator to control its operation.
Claim 15
Dependent Claim
81 words
Apparatus according to claim 6 wherein both said positive one-half cycle difference pulse generating means each include two outputs, a first output emitting a P difference pulse at each occurrence when a test signal one-half cycle has a duration greater than said one-half an average period of the test signal, a second output emitting a N difference pulse at each occurrence when a test signal one-half cycle has a duration less than said one-half an average period of the test signal.
Claim 16
Dependent Claim
151 words
Apparatus according to claim 9 wherein said means measuring the width of each of said generated difference pulses comprises: means for combining the first and second difference pulse outputs of both the positive one-half cycle difference pulse generating means and the negative one-half cycle difference pulse generating means into a single output, means receiving combined P and N pulses from said single output for emitting an electrical pulse coincident in time with each P and N pulse applied thereto, the magnitude of said output electrical pulses being proportional to said one-half the average period of said test signal, means receiving the output of said emitting means for integrating each of its said output electrical pulses, and a peak detector monitoring an output of said integrating means, whereby the largest integrated value of the emitting means output pulses for a time is a measure of peak-per-cycle phase jitter of said test signal.
Claim 17
Dependent Claim
138 words
Apparatus according to claim 9 wherein said means measuring the width of each of said generated difference pulses comprises: means combining the first outputs of said one-half cycle difference pulse generating means and for adjusting the magnitude of their N pulses by a factor proportional to said one-half the average period of said test signal, means receiving the adjusted magnitude P pulses and adjusted magnitude N pulses for developing at a single output a signal level that is driven in one direction by the adjusted magnitude P pulses and an opposite direction by the adjusted magnitude N pulses, and a peak-to-peak detector for measuring the maximum signal level change at the single output of said signal level developing means, whereby the maximum signal level change is a measure of the total peak-to-peak phase jitter of said test signal.
Claim 18
Dependent Claim
100 words
Apparatus according to claim 9 wherein said means measuring the width of each of said generated difference pulses comprises: means for combining the first and second difference pulse outputs of both the positive one-half cycle difference pulse generating means and the negative one-half cycle difference pulse generating means into a single output, means for digitally counting the duration of the P and N pulses at said single output, and means for detecting the maximum count of said digital counting means, whereby the maximum pulse duration count for a time is a measure of peak-per-cycle phase jitter of said test signal.
Claim 19
Dependent Claim
130 words
Apparatus according to claim 9 wherein said means measuring the width of each of said generated difference pulses comprises: a digital up-down counter, means combining the first outputs of said one-half cycle difference pulse generating means for driving said counter in one direction a count proportional to the width of said P pulses and to said test signal one-half average period, means combining the outputs of said one-half Cycle difference pulse generating means for driving said counter in an opposite direction a count proportional to the width of said N pulses and to said test signal one-half average period, means monitoring said counter for detecting the maximum count difference of the counter, whereby said maximum count difference is a measure of the total peak-to-peak phase jitter of said test signal.
Claim 20
Dependent Claim
241 words
Apparatus for measuring a disturbance in the periodicity of zero crossings of an alternating current signal, comprising: means responsive to said alternating current signal for generating a reference pulse upon the occurrence of detected zero crossings of the alternating current signal, said reference pulse generating means including an input receiving a signal that sets the duration of said reference pulse, means receiving said reference pulse and said alternating current signal for emitting a first output signal proportional to an excess in time of the period of occurrence of said detected zero crossings relative to the width of said reference pulse, and for emitting a second output signal proportional to an excess in time of the width of said reference pulse relative to the period of occurrence of said detected zero crossings, means receiving said first and second output signals for applying a signal to the pulse duration control input of said reference pulse generating means that is proportional to the average difference in the signals of said first and second outputs, thereby to form a closed loop system that assures the reference pulse generating means output to be proportional to the fundamental frequency of said alternating current signal, and means receiving said first and second output signals and responsive to the duration of said reference pulse for developing an output signal indicative of the first and second output signals as a function of the average frequency of said alternating current signal.
Claim 21
Dependent Claim
241 words
Apparatus for measuring a disturbance in the periodicity of zero crossings of an alternating current signal, comprising: means responsive to said alternating current signal for generating a reference pulse upon the occurrence of detected zero crossings of the alternating current signal, said reference pulse generating means including an input receiving a signal that sets the duration of said reference pulse, means receiving said reference pulse and said alternating current signal for emitting a first output signal proportional to an excess in time of the period of occurrence of said detected zero crossings relative to the width of said reference pulse, and for emitting a second output signal proportional to an excess in time of the width of said reference pulse relative to the period of occurrence of said detected zero crossings, means receiving said first and second output signals for applying a signal to the pulse duration control input of said reference pulse generating means that is proportional to the average difference in the signals of said first and second outputs, thereby to form a closed loop system that assures the reference pulse generating means output to be proportional to the fundamental frequency of said alternating current signal, and means receiving said first and second output signals and responsive to the duration of said reference pulse for developing an output signal indicative of the first and second output signals as a function of the average frequency of said alternating current signal.
Claim 22
Independent Claim
81 words
A method of measuring a disturbance in the periodicity of zero crossings of an alternating current signal, comprising: measuring the time duration between detected zero crossings of said alternating current signal, determining an average time period between the detected zero crossings of said alternating current signal, determining a difference of the time duration between successive detected zero crossings with the average period of recurrence of the detected zero crossings, and expressing said time difference as a function of said average period.
Claim 23
Independent Claim
81 words
A method of measuring a disturbance in the periodicity of zero crossings of an alternating current signal, comprising: measuring the time duration between detected zero crossings of said alternating current signal, determining an average time period between the detected zero crossings of said alternating current signal, determining a difference of the time duration between successive detected zero crossings with the average period of recurrence of the detected zero crossings, and expressing said time difference as a function of said average period.
Claim 24
Dependent Claim
22 words
The method as defined by claim 15 wherein said detected zero crossings occur once each full cycle of said alternating current signal.
Claim 25
Dependent Claim
64 words
Apparatus for measuring a disturbance in the periodicity of zero crossings of an alternating current signal, comprising: means responsive to said signal for comparing the time between successive detected zero crossings of said signal to an average time period between said detected zero crossings, and means responsive to said comparison means for expressing said time comparison as a proportion of said average time period.
Claim 26
Dependent Claim
64 words
Apparatus for measuring a disturbance in the periodicity of zero crossings of an alternating current signal, comprising: means responsive to said signal for comparing the time between successive detected zero crossings of said signal to an average time period between said detected zero crossings, and means responsive to said comparison means for expressing said time comparison as a proportion of said average time period.
Claim 27
Dependent Claim
126 words
Apparatus for measuring a disturbance in the periodicity of zero crossings of an alternating current signal, comprising: means responsive to said signal for emitting a pulse having a duration equal to a difference in time between successive detected zero crossings of said signal and an average time period between said detected zero crossings, a P type pulse being emitted on each occurrence when the time between successive detected zero crossings exceeds said average time period, and an N type pulse being emitted on each occurrence when said average time period exceeds the time between successive detected zero crossings, and means responsive to said pulse emitting means for measuring the duration of the longest P or N type pulse as a proportion of said average time period.
Claim 28
Dependent Claim
126 words
Apparatus for measuring a disturbance in the periodicity of zero crossings of an alternating current signal, comprising: means responsive to said signal for emitting a pulse having a duration equal to a difference in time between successive detected zero crossings of said signal and an average time period between said detected zero crossings, a P type pulse being emitted on each occurrence when the time between successive detected zero crossings exceeds said average time period, and an N type pulse being emitted on each occurrence when said average time period exceeds the time between successive detected zero crossings, and means responsive to said pulse emitting means for measuring the duration of the longest P or N type pulse as a proportion of said average time period.
Claim 29
Dependent Claim
138 words
Apparatus for measuring a disturbance in the periodicity of zero crossings of an alternating current signal, comprising: means responsive to said signal for emitting a pulse having a duration equal to a difference in time between successive detected zero crossings of said signal and an average time period between said detected zero crossings, a P type pulse being emitted on each occurrence when the time between successive detected zero crossings exceeds said average time period, and an N type pulse being emitted on each occurrence when said average time period exceeds the time between successive detected zero crossings, and means responsive to said pulse emitting means for separately totalling the duration of the P and N type pulses for a time and for expressing a time difference of said totals as a proportion of said average time period.
Claim 30
Dependent Claim
138 words
Apparatus for measuring a disturbance in the periodicity of zero crossings of an alternating current signal, comprising: means responsive to said signal for emitting a pulse having a duration equal to a difference in time between successive detected zero crossings of said signal and an average time period between said detected zero crossings, a P type pulse being emitted on each occurrence when the time between successive detected zero crossings exceeds said average time period, and an N type pulse being emitted on each occurrence when said average time period exceeds the time between successive detected zero crossings, and means responsive to said pulse emitting means for separately totalling the duration of the P and N type pulses for a time and for expressing a time difference of said totals as a proportion of said average time period.
References Cited (Backward Citations)
US3533402A
Cited
US3675485A
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USPTO Annuity & Maintenance Windows
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| 3.5 Years (Year 4) | 1976-06-04 | 1976-12-04 | 1977-06-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-04 | 1980-12-04 | 1981-06-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-04 | 1984-12-04 | 1985-06-05 | $7700.00 | Window Closed / Lapsed |