Patent US5438254A successfully refreshed from Google Patents.
US5438254A
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US
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Phase difference measuring device
Assignee: Individual
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Filing: 1994-07-29
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Granted: 1995-08-01
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Expires: 2014-07-29
Abstract
Abstract A phase difference measuring device includes a phase detector, a low-pass filter/voltage controlled oscillator, a reference signal selector for selecting either an internal reference signal or an external reference signal as a reference signal, a phase comparator for comparing an undertest signal with the selected reference signal and obtaining a phase difference between the two compared signal. The internal reference signal is selected when the undertest signal is a jittering signal, and the external reference signal is selected when the undertest signal is a wandering signal. The undertest signal, the selected reference signal, and a relatively high frequency clock signal from external are sent to the phase comparator and a phase difference between the undertest signal and the selected reference signal is counted by the relatively high frequency clock signal.
Inventors
- 👤 Edmond Y. Ho
- 👤 Fu-chin Yang
- 👤 Jung-lung Lin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 17:00
CPC Classifications
G; G01; G01R; G01R23/00; G01R23/16; G01R23/20; G01R25/00; G01R25/08; G01R31/00; G01R31/28; G01R31/30
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
207 words
A phase difference measuring device comprising a phase detector, a low-pass filter/voltage controlled oscillator, a reference signal selector for selecting either an internal reference signal or an external reference signal, a phase comparator for comparing an undertest signal with the selected reference signal and obtaining a phase difference between the two compared signals; wherein the phase detector together with the low-pass filter/voltage controlled oscillator constitute a phase lock loop for detecting the phase of the undertest signal; the internal reference signal outputted from the low-pass filter/voltage controlled oscillator and the external reference signal are sent to the reference signal selector, and the internal reference signal is selected when the undertest signal is a jittering signal, and the external reference signal is selected when the undertest signal is a wandering signal; the undertest signal and the selected reference signal are sent to the phase comparator for obtaining a phase difference therebetween; an initialization signal for initializing the phase comparator and a relatively high frequency clock signal for counting the phase difference are sent to the phase comparator; a phase difference between the undertest signal and the selected reference signal is counted in the phase comparator and a digital signal representing the phase difference outputted from the phase comparator.
Claim 2
Dependent Claim
207 words
A phase difference measuring device comprising a phase detector, a low-pass filter/voltage controlled oscillator, a reference signal selector for selecting either an internal reference signal or an external reference signal, a phase comparator for comparing an undertest signal with the selected reference signal and obtaining a phase difference between the two compared signals; wherein the phase detector together with the low-pass filter/voltage controlled oscillator constitute a phase lock loop for detecting the phase of the undertest signal; the internal reference signal outputted from the low-pass filter/voltage controlled oscillator and the external reference signal are sent to the reference signal selector, and the internal reference signal is selected when the undertest signal is a jittering signal, and the external reference signal is selected when the undertest signal is a wandering signal; the undertest signal and the selected reference signal are sent to the phase comparator for obtaining a phase difference therebetween; an initialization signal for initializing the phase comparator and a relatively high frequency clock signal for counting the phase difference are sent to the phase comparator; a phase difference between the undertest signal and the selected reference signal is counted in the phase comparator and a digital signal representing the phase difference outputted from the phase comparator.
Claim 3
Dependent Claim
161 words
A phase difference measuring device as claimed in claim 1, wherein the phase comparator comprises a first divider for receiving the undertest signal and outputting a first divided signal in response, a second divider for receiving the selected reference signal and outputting a second divided signal in response, an initialization circuit for receiving the initialization signal and providing a reset signal to the first and the second dividers, an AND gate coupled to receive the relatively high frequency clock signal and output a clock signal in response,.a counter coupled to receive the clock signal and the second divided signal and output a counted signal, a latch coupled to receive the counted signal and output the digital signal representing the phase difference in response to every rising edge of the first divided signal; wherein the second divided signal resets the counter at its falling edge of each cycle and enables the counter to count again at its rising edge of each cycle.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-07-31 | 1999-01-30 | 1999-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-07-31 | 2003-01-30 | 2003-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-07-31 | 2007-01-30 | 2007-08-01 | $7700.00 | Window Closed / Lapsed |