US3911359A
Expired / Lapsed
US
⏱️ 0.0 years remaining
True RMS converters
Assignee: Gemalto Terminals Ltd
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Filing: 1974-06-13
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Granted: 1975-10-07
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Expires: 1994-06-13
Abstract
Abstract An RMS converter of the type wherein the energy of the input signal is dissipated in a first resistor and a second signal, in a form which lends itself to measurement, is generated which dissipates an equal amount of heat in a second resistor, the second signal being derived from measurement of temperature differential between the first and second resistors. This converter is characterised by a circuit for applying power to both resistors so that the total power received by each resistor remains substantially constant.
Inventors
- 👤 Eric Metcalf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 00:52
CPC Classifications
G; G01; G01R; G01R19/00; G01R19/22; G01R19/225
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
188 words
A device for use in measuring the root mean square value of an input signal, comprising first and second substantially identical heating elements, means for applying to the first heating element a signal representative of the input signal, means for sensing a temperature differential between the first and second heating elements and for providing a signal representative thereof, a feedback circuit connected to receive the signal representative of temperature differential and to apply a feedback signal to the second heating element so as to reduce the said temperature differential, a source of reference signal, and an adjustable A.C. power source responsive to the reference signal and a signal from the feedback ciRcuit to deliver to each of the first and second heating elements an amount of power dependent of the difference between the reference signal and said signal from the feedback circuit, said power source being arranged to deliver substantially the same amount of power to each of the said heating elements, whereby the total power received by each heating element remains substantially constant and the feedback signal is representative of the RMS value of the input signal.
Claim 2
Independent Claim
188 words
A device for use in measuring the root mean square value of an input signal, comprising first and second substantially identical heating elements, means for applying to the first heating element a signal representative of the input signal, means for sensing a temperature differential between the first and second heating elements and for providing a signal representative thereof, a feedback circuit connected to receive the signal representative of temperature differential and to apply a feedback signal to the second heating element so as to reduce the said temperature differential, a source of reference signal, and an adjustable A.C. power source responsive to the reference signal and a signal from the feedback ciRcuit to deliver to each of the first and second heating elements an amount of power dependent of the difference between the reference signal and said signal from the feedback circuit, said power source being arranged to deliver substantially the same amount of power to each of the said heating elements, whereby the total power received by each heating element remains substantially constant and the feedback signal is representative of the RMS value of the input signal.
Claim 3
Dependent Claim
39 words
A device according to claim 1, wherein the means for sensing temperature differential between the first and second heating elements comprises respective first and second substantially identical thermocouples in thermal contact with the respective first and second heating elements.
Claim 4
Dependent Claim
64 words
A circuit according to claim 1, wherein the feedback circuit comprises an amplifier connected to receive and amplify said signal representative of temperature differential and a function generator circuit arranged to receive the amplified signal and to produce an output, the amplitude whereof is linearly related to the square root of the amplitude of the said amplified signal, said output constituting said feedback signal.
Claim 5
Dependent Claim
33 words
A device according to claim 1, wherein the adjustable A.C. power source comprises a modulator connected to receive at least one DC signal and providing an output representative thereof which is alternating current.
Claim 6
Independent Claim
266 words
A device for use in measuring the root mean square value of an input signal comprising first and second substantially identical heating elements, means for applying to the first heating element a signal representative of the input signal, means for sensing a temperature differential between the first and second heating elements and for providing a signal representative thereof, a feedback circuit connected to receive the signal representative of temperature differential and to apply a feedback signal having an amplitude proportional to the square root of the amplitude of the signal representative of temperature differential to the second heating element so as to reduce the said temperature differential, a source of reference signal, a level control circuit having an input and an output and receiving at its input the signal representative of temperature differential and the reference signal and producing at its output a control signal representative of the square root of the difference between the signals at its input, an adjustable A.C. power source connected to receive the control signal and connected to the first and second heating elements respectively for delivering substantially the same power to each of the said heating elements, said source being adapted to adjust the power in response to the control signal so that the total power received by the second heating element from the feedback signal and from the power source remains substantially constant, whereby a signal from the feedback circuit representative of the feedback signal applied to the second heating element to reduce the temperature differential serves as an output representative of the RMS value of the input signal.
Claim 7
Independent Claim
266 words
A device for use in measuring the root mean square value of an input signal comprising first and second substantially identical heating elements, means for applying to the first heating element a signal representative of the input signal, means for sensing a temperature differential between the first and second heating elements and for providing a signal representative thereof, a feedback circuit connected to receive the signal representative of temperature differential and to apply a feedback signal having an amplitude proportional to the square root of the amplitude of the signal representative of temperature differential to the second heating element so as to reduce the said temperature differential, a source of reference signal, a level control circuit having an input and an output and receiving at its input the signal representative of temperature differential and the reference signal and producing at its output a control signal representative of the square root of the difference between the signals at its input, an adjustable A.C. power source connected to receive the control signal and connected to the first and second heating elements respectively for delivering substantially the same power to each of the said heating elements, said source being adapted to adjust the power in response to the control signal so that the total power received by the second heating element from the feedback signal and from the power source remains substantially constant, whereby a signal from the feedback circuit representative of the feedback signal applied to the second heating element to reduce the temperature differential serves as an output representative of the RMS value of the input signal.
Claim 8
Dependent Claim
24 words
A device according to claim 3, comprising means for applying said amplified signal to said power source as said signal from the feedback circuit.
References Cited (Backward Citations)
US3435319A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-06 | 1979-04-07 | 1979-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-06 | 1983-04-07 | 1983-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-06 | 1987-04-07 | 1987-10-07 | $7700.00 | Window Closed / Lapsed |