US3596175A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical measuring apparatus for providing an output signal at an output branch characteristic of the relationship of impedances presented at first and second side branches at the frequency of energy applied at an input branch
Assignee: Individual
•
Filing: 1968-08-23
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Granted: 1971-07-27
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Expires: 1988-08-23
Abstract
Abstract A radio frequency signal source delivers a signal to an input branch through a harmonic filter to provide an output signal on an output branch indicated by indicating means representative of the difference in impedance between a standard impedance connected to one side branch and an unknown impedance connected to the other side branch. A pair of equal resistances connect the high terminal of the input branch to the respective high terminals of the respective side branches. A higher resistor intercouples the high terminals of the side branches so that when the side branches are terminated in their characteristic impedance, typically 50 ohms, the impedance presented at the input branch is substantially equal to the input branch characteristic impedance, typically 50 ohms. Means including isolating resistors and a bridge circuit couples the side branch high terminals to the output branch high terminal, all four branches having low, or grounded terminals, that are interconnected.
Inventors
- 👤 Andrew Alford
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 13:15
CPC Classifications
G; G01; G01R; G01R27/00; G01R27/02
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
238 words
In an electrical circuit, operative over a broad band of frequencies, for providing an output signal related to the difference in impedance presented by an unknown impedance connected to a first side branch by a transmission line and a standard impedance connected to a second side branch, the electrical circuit being of the type having an input branch for accepting an AC input signal, a first resistor connected between the input branch and the second side branch, a second resistor connected between the input branch and the second side branch, a third resistor connected between the side branches to form a delta circuit with the first and second resistors, detecting means for detecting the difference in electrical potential between the side branches, and means coupling the detecting means to the side branches, the improvement wherein the means coupling the detecting means to the side branches comprise resistors which provide appreciable impedance at the higher frequencies in the broad band where the impedance of the detecting means falls to a low value, and the third resistor in the delta circuit differs from the value of the other two resistors in the delta circuit, the value of the third resistors being such as to cause the impedance seen looking into the first side branch to match, over a large portion of the broad band, the characteristic impedance of the transmission line connecting the unknown impedance to the first side branch.
Claim 2
Dependent Claim
238 words
In an electrical circuit, operative over a broad band of frequencies, for providing an output signal related to the difference in impedance presented by an unknown impedance connected to a first side branch by a transmission line and a standard impedance connected to a second side branch, the electrical circuit being of the type having an input branch for accepting an AC input signal, a first resistor connected between the input branch and the second side branch, a second resistor connected between the input branch and the second side branch, a third resistor connected between the side branches to form a delta circuit with the first and second resistors, detecting means for detecting the difference in electrical potential between the side branches, and means coupling the detecting means to the side branches, the improvement wherein the means coupling the detecting means to the side branches comprise resistors which provide appreciable impedance at the higher frequencies in the broad band where the impedance of the detecting means falls to a low value, and the third resistor in the delta circuit differs from the value of the other two resistors in the delta circuit, the value of the third resistors being such as to cause the impedance seen looking into the first side branch to match, over a large portion of the broad band, the characteristic impedance of the transmission line connecting the unknown impedance to the first side branch.
Claim 3
Dependent Claim
37 words
The electrical circuit according to claim 1, wherein the improvement further is characterized in that the standard impedance has a value matching the characteristic impedance of the transmission line which is connected to the first side branch.
Claim 4
Dependent Claim
78 words
The electrical circuit according to claim 1, the improvement being further characterized by a full wave rectifying bridge in the detecting means, the rectifying bridge being balanced with respect to the the side branches to cause the rectifying bridge to have an equal effect upon the impedance seEn looking into each side branch, and an indicator connected across diagonally opposite junctions of the bridge to cause the indicator to respond to the rectified current flowing in the bridge.
Claim 5
Dependent Claim
67 words
The electrical circuit according to claim 1, the improvement being further characterized by a bridge in the detecting means, the bridge being formed by four resistive arms, the resistive elements in two arms of the bridge being bolometers, and the bridge being balanced with respect to the side branches to cause the bridge to have an equal effect upon the impedance seen looking into each side branch.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-07-26 | 1975-01-25 | 1975-07-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-07-26 | 1979-01-25 | 1979-07-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-07-26 | 1983-01-25 | 1983-07-27 | $7700.00 | Window Closed / Lapsed |