Patent US4449223A successfully refreshed from Google Patents.
US4449223A
Expired / Lapsed
US
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Eye opening monitor
Assignee: Raytheon Co
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Filing: 1982-04-30
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Granted: 1984-05-15
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Expires: 2002-04-30
Abstract
Abstract An eye opening monitor for a binary waveform such as provided as the video output of a demodulator. At the decision sample time, the video is compared to -V th and +V th reference voltages to determine if it falls in the range defined therebetween. If it does, a counter is reset. Because the carry-out pulses of the counter are used to produce -V th and +V th , the range defined therebetween is decreased by the additional time required to count to the carry-out after the counter is reset. The loop stabilizes with the range from -V th and +V th being quantitatively indicative of the eye opening. A voltage derived from V th is visually displayed.
Inventors
- 👤 Nathan A. Liskov
- 👤 Robert G. Curtis
- 👤 Caesar J. Favaloro
- 👤 Gregory L. Pence
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 17:42
CPC Classifications
G; G01; G01R; G01R19/00; G01R19/165; G01R19/16533; G01R19/16557; G01R31/00; G01R31/28; G01R31/317; G01R31/31708; H; H03; H03K; H03K5/00; H03K5/22; H03K5/24
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
169 words
An eye opening monitor circuit for a QPSK demodulator, comprising: means for comparing the in-phase signal from said demodulator to a voltage range defined by -V th to +V th , the output of said in-phase comparing means being a first input to an OR gate; means for comparing the quadrature-phase signal from said demodulator to said voltage range defined by -V th to +V th , the output of said quadrature-phase comparing means being the second input to said OR gate; means responsive to the output of said OR gate for generating said -V th and +V th voltages, the range of which is decreased when either said in-phase or quadrature-phase signal is within said range defined by -V th and +V th voltages; said generating means comprising a clocked counter providing a carry-out pulse at a predetermined count, the period between carry-out pulses being altered by resetting said counter with said output of said OR gate; and means for providing a visual display proportional to said range.
Claim 2
Dependent Claim
169 words
An eye opening monitor circuit for a QPSK demodulator, comprising: means for comparing the in-phase signal from said demodulator to a voltage range defined by -V th to +V th , the output of said in-phase comparing means being a first input to an OR gate; means for comparing the quadrature-phase signal from said demodulator to said voltage range defined by -V th to +V th , the output of said quadrature-phase comparing means being the second input to said OR gate; means responsive to the output of said OR gate for generating said -V th and +V th voltages, the range of which is decreased when either said in-phase or quadrature-phase signal is within said range defined by -V th and +V th voltages; said generating means comprising a clocked counter providing a carry-out pulse at a predetermined count, the period between carry-out pulses being altered by resetting said counter with said output of said OR gate; and means for providing a visual display proportional to said range.
Claim 3
Dependent Claim
23 words
The combination in accordance with claim 1 wherein said -V th and +V th voltages are produced in response to said carry-out pulses.
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) | 1987-05-15 | 1987-11-14 | 1988-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-05-15 | 1991-11-14 | 1992-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-05-15 | 1995-11-14 | 1996-05-15 | $7700.00 | Window Closed / Lapsed |