US3735150A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low noise phase detector
Assignee: United States Department of the Navy
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Filing: 1971-12-21
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Granted: 1973-05-22
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Expires: 1991-12-21
Abstract
Abstract A phase sensitive detector employing a pair of limiting amplifiers, wherein the outputs are respectively connected to a current switch and a pair of in-line-decision switches. The inline-decision switches and the current switch provide a current on one of two lines that is indicative of a phase difference between two periodic waveforms as they appear on the input of the limiting amplifier. The switching properties are controlled as a function of each waveforms'' zero-cross-over point in time. This circuit measures phase difference with high accuracy and resolution and with minimal degradation of the accuracy when measuring weak or noisy signals as a result of employing all zero cross-overs.
Inventors
- 👤 R Harris
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 04:20
CPC Classifications
G; G01; G01R; G01R23/00
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
183 words
A phase detector for measuring a phase difference between two periodic signals of similar frequency comprising: means for shaping a first and second signal; means for limiting each of said first and second signals coupled to said shaping means; means for selectively applying a current of a determined value to one of two current paths as a function of said first signal, said means for selectively applying said current being connected to said limiting means for said first signal; means for switching said cUrrent in said one of two current paths to selected terminals of a limiting amplifier wherein said means for switching said current is connected to said limiting means for said second signal and said switching means being controlled by said second signal; means for generating a d.c. level proportional to the current applied to one of said selected terminals; means for providing a voltage output connected to said d.c. level generating means such that a voltage level which is representative of a phase difference between said first and second signal is provided for as a result of said d.c. level.
Claim 2
Dependent Claim
183 words
A phase detector for measuring a phase difference between two periodic signals of similar frequency comprising: means for shaping a first and second signal; means for limiting each of said first and second signals coupled to said shaping means; means for selectively applying a current of a determined value to one of two current paths as a function of said first signal, said means for selectively applying said current being connected to said limiting means for said first signal; means for switching said cUrrent in said one of two current paths to selected terminals of a limiting amplifier wherein said means for switching said current is connected to said limiting means for said second signal and said switching means being controlled by said second signal; means for generating a d.c. level proportional to the current applied to one of said selected terminals; means for providing a voltage output connected to said d.c. level generating means such that a voltage level which is representative of a phase difference between said first and second signal is provided for as a result of said d.c. level.
Claim 3
Dependent Claim
41 words
The phase detector is claimed in claim 1, wherein said means for limiting and means for shaping comprises: a pair of limiting amplifiers adjusted to produce an identical rise time and an identical amplitude for said first and said second signal.
Claim 4
Dependent Claim
57 words
The phase detector as claimed in claim 1, wherein said means for selectively applying a current comprises: a first and second transistor, operated within them saturated mode wherein only said first transistor turns on when said first signal is greater than OV, and only said second transistor turns on when first signal is less than 0 volts.
Claim 5
Dependent Claim
31 words
The phase detector as claimed in claim 1, wherein said means for selectively switching said current comprises: two pairs of transistors, operated within their saturated mode wherein each pair is connected.
Claim 6
Dependent Claim
204 words
A phase detector for measuring a phase difference between two periodic signals of similar frequency comprising: a first and second limiting amplifier each having an input and an output wherein each input provides means for connecting a first and a second signal; the output of said first limiting amplifier connected to a current switch such that when said first signal is greater than a reference a current is switched to a first in-line decision switch and when said first signal is less than said reference said current is switched to a second in-line-decision switch; said output of said second limiting amplifier connected to said first and said second in-line-decision switch such that when said second signal is greater than said reference, said current is applied to a first terminal and when said second signal is less than said reference said current is applied to a second terminal; a third limiting amplifier means connected to said first and second terminals providing a current output proportional to a current change between said first and second signal, a first and a second operational amplifier connected to said third limiting amplifier means to provide a voltage level proportional to said current change between said first and second signal.
Claim 7
Dependent Claim
204 words
A phase detector for measuring a phase difference between two periodic signals of similar frequency comprising: a first and second limiting amplifier each having an input and an output wherein each input provides means for connecting a first and a second signal; the output of said first limiting amplifier connected to a current switch such that when said first signal is greater than a reference a current is switched to a first in-line decision switch and when said first signal is less than said reference said current is switched to a second in-line-decision switch; said output of said second limiting amplifier connected to said first and said second in-line-decision switch such that when said second signal is greater than said reference, said current is applied to a first terminal and when said second signal is less than said reference said current is applied to a second terminal; a third limiting amplifier means connected to said first and second terminals providing a current output proportional to a current change between said first and second signal, a first and a second operational amplifier connected to said third limiting amplifier means to provide a voltage level proportional to said current change between said first and second signal.
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) | 1976-05-21 | 1976-11-20 | 1977-05-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-21 | 1980-11-20 | 1981-05-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-21 | 1984-11-20 | 1985-05-22 | $7700.00 | Window Closed / Lapsed |