US3626290A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High-frequency power measuring circuit employing two self-balancing bridges
Assignee: Narda Microwave Corp
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Filing: 1967-11-30
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Granted: 1971-12-07
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Expires: 1987-11-30
Abstract
Abstract A high-precision circuit for measuring radiofrequency power by the direct current substitution method, wherein two selfbalancing bridges are used; the first bridge containing a thermistor subjected to the radiofrequency power, and the second bridge containing a reference thermistor for establishing a temperature-compensated reference level.
Inventors
- 👤 Edward E Aslan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 08:38
CPC Classifications
G; G01; G01R; G01R21/00; G01R21/02; G01R5/00; G01R5/22
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
148 words
A temperature compensated high-frequency power measuring circuit comprising first and second self-balancing direct current bridge circuits each having a first diagonal with first and second terminals across which a rebalancing signal is applied and a second diagonal across which an error signal may be obtained, and each of said circuits containing a similar temperature variable resistor in one arm thereof which exhibits resistance changes in response to high frequency power changes and in response to ambient temperature changes, means for establishing the same predetermined direct voltage level across the first diagonal of each bridge when no high-frequency power is being applied, means for connecting said first terminals to a source of reference potential, and means for measuring the difference voltage between said second terminals as an indication of highfrequency power being measured after high-frequency power is applied to the temperature variable resistor in one of said bridges only.
Claim 2
Dependent Claim
148 words
A temperature compensated high-frequency power measuring circuit comprising first and second self-balancing direct current bridge circuits each having a first diagonal with first and second terminals across which a rebalancing signal is applied and a second diagonal across which an error signal may be obtained, and each of said circuits containing a similar temperature variable resistor in one arm thereof which exhibits resistance changes in response to high frequency power changes and in response to ambient temperature changes, means for establishing the same predetermined direct voltage level across the first diagonal of each bridge when no high-frequency power is being applied, means for connecting said first terminals to a source of reference potential, and means for measuring the difference voltage between said second terminals as an indication of highfrequency power being measured after high-frequency power is applied to the temperature variable resistor in one of said bridges only.
Claim 3
Dependent Claim
72 words
A temperature compensated high-frequency power measuring circuit according to claim 1, wherein the self-balancing of the bridge circuits is effected by transistor differential amplifier means having its input connected across the second diagonal of each bridge and a transistor amplifier controlled by said differential amplifier means for establishing the rebalancing signal applied to said first diagonal of each said bridge, and wherein said transistor differential amplifier means includes an inverse feedback amplifier.
Claim 4
Dependent Claim
51 words
A temperature compensated high-frequency power measuring circuit according to claim 2, including a potentiometer between two arms of each bridge circuit, and an adjustable tap on said potentiometer connected to one side of said differential amplifier means to permit manual adjustment Of the voltage across said first diagonal of the bridge.
Claim 5
Dependent Claim
23 words
A temperature compensated high-frequency power measuring circuit according to claim 1, wherein said first and second self-balancing direct current bridges are electrically independent.
Claim 6
Dependent Claim
17 words
A temperature compensated high-frequency power measuring circuit according to claim 1, utilizing direct current supply means only.
Claim 7
Dependent Claim
26 words
A temperature compensated high frequency power measuring circuit according to claim 1, wherein said temperature variable resistors are both subject to the same ambient temperature conditions.
Claim 8
Dependent Claim
28 words
A temperature compensated high-frequency power measuring circuit according to claim 1, wherein said first and second self-balancing direct current bridge circuits each contain elements having substantially similar characteristics.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-06 | 1975-06-07 | 1975-12-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-06 | 1979-06-07 | 1979-12-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-06 | 1983-06-07 | 1983-12-07 | $7700.00 | Window Closed / Lapsed |