Patent US3890841A successfully refreshed from Google Patents.
US3890841A
Expired / Lapsed
US
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Thermal noise measurement system
Assignee: Forschungszentrum Jülich
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Filing: 1973-06-13
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Granted: 1975-06-24
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Expires: 1993-06-13
Abstract
Abstract A system for measuring temperatures using the thermal-noise electrical output of a conductive element in which a reference resistor and the conductive element are connected by a sampling switch arrangement to two amplifiers provided with filters whose band width or characteristic pass frequency corresponds to the noice-voltage frequency. The outputs of the latter are applied to a multiplier or squaring circuit and the latter supplies an analog or d-c signal to the output stage via a commutating switch synchronized with the sampleing switch. The switch arrangement is such that both amplifier-filter paths are either simultaneously connected to the reference resistor or with the measuring resistor.
Inventors
- 👤 Heinz Brixy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:10
CPC Classifications
G; G01; G01K; G01K1/00; G01K1/02; G01K1/024; G01K1/20; G01K7/00; G01K7/30
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
353 words
A system for the measurement of temperature, comprising: a measuring branch having a measuring resistor adapted to generate a thermal-noise signal proportional to absolute measure temperature and at least one cable in series with said measuring resistor; a reference branch including a reference resistor at a reference temperature and at least one cable in series therewith; a pair of amplifier paths each comprising a preamplifier, a filter connected to the output of the respective preamplifier, and a main amplifier energized through the respective filter; switch means for alternately connecting said branches to said amplifier paths so that both amplifier paths are simultaneously connected in one switch condition with one branch and in another switch condition with the other branch; a multiplier circuit receiving inputs from the main amplifier of both said amplifier paths for producing an output representing the product of the signals applied thereto; a differential amplifier having a pair of inputs each connected to a respective storage capacitor; a commutating switch synchronized with said switch means for applying the output of said multiplier corresponding to connection of one of said branches to both said amplifier paths to one of said capacitors in one such condition and the output of said multiplier corresponding to connection of the other of said branches to both said amplifier paths to the other capacitor in said other switch condition; an integrator receiving an output from said differential amplifier; and read out means connected to said integrator for registering the temperature at said measuring resistor, said switch means including two single-pole double-throw switches having respective output contacts connected to the preamplifier of each of said amplifier paths, said measuring branch comprising a first cable connected to one input contact of one of said single-pole double-throw switches and a second cable connected to the corresponding input of the other single-pole doublethrow switches, said reference branch having a first cable connected to the other input contact of said one of said single-pole double-throw switches and a second cable connected to the other input contact of the other single-pole doublethrow switch, said single-pole double-throw switches being ganged for joint operation.
Claim 2
Independent Claim
353 words
A system for the measurement of temperature, comprising: a measuring branch having a measuring resistor adapted to generate a thermal-noise signal proportional to absolute measure temperature and at least one cable in series with said measuring resistor; a reference branch including a reference resistor at a reference temperature and at least one cable in series therewith; a pair of amplifier paths each comprising a preamplifier, a filter connected to the output of the respective preamplifier, and a main amplifier energized through the respective filter; switch means for alternately connecting said branches to said amplifier paths so that both amplifier paths are simultaneously connected in one switch condition with one branch and in another switch condition with the other branch; a multiplier circuit receiving inputs from the main amplifier of both said amplifier paths for producing an output representing the product of the signals applied thereto; a differential amplifier having a pair of inputs each connected to a respective storage capacitor; a commutating switch synchronized with said switch means for applying the output of said multiplier corresponding to connection of one of said branches to both said amplifier paths to one of said capacitors in one such condition and the output of said multiplier corresponding to connection of the other of said branches to both said amplifier paths to the other capacitor in said other switch condition; an integrator receiving an output from said differential amplifier; and read out means connected to said integrator for registering the temperature at said measuring resistor, said switch means including two single-pole double-throw switches having respective output contacts connected to the preamplifier of each of said amplifier paths, said measuring branch comprising a first cable connected to one input contact of one of said single-pole double-throw switches and a second cable connected to the corresponding input of the other single-pole doublethrow switches, said reference branch having a first cable connected to the other input contact of said one of said single-pole double-throw switches and a second cable connected to the other input contact of the other single-pole doublethrow switch, said single-pole double-throw switches being ganged for joint operation.
Claim 3
Dependent Claim
45 words
The system defined in claim 1 further comprising a respective narrow-band amplifier connectible between the output of the preamplifier of each amplifier path and said multiplier, said reference branch including a variable capacitor, a variable inductor and a variable resistance enabling balancing of said branches.
Claim 4
Dependent Claim
20 words
The system defined in claim 1 wherein said measuring resistor is disposed in the radiation field of a nuclear reactor.
Claim 5
Dependent Claim
103 words
The system defined in claim 1 wherein said measuring resistor includes an elongated housing, a thermal-noise-generating strand composed of a metal from the group which consists of tungsten, tantalum, molybdenum, nioblum, titanium, zirconium, chromium, nickel and iron, and alloys of chromium, nickel and iron, wound in a plurality of turns along the length of said housing, a body of electrically insulating ceramic material separating said turns from one another and composed of at least ceramic from the group which consists of alumina, beryllia, thoria and magnesia, and conductors extending into said housing and connecting said strand to the cable of said measuring branch.
Claim 6
Dependent Claim
24 words
The system defined in claim 4 wherein said strand has a cross-section corresponding to a circle with a diameter between 5 and 50 microns.
Claim 7
Dependent Claim
26 words
The system defined in claim 5 wherein said body is provided with a multiplicity of passages, said strand passing through said passages in alternately opposite directions.
Claim 8
Dependent Claim
18 words
The system defined in claim 6 wherein said switch means includes at least one pair of field-effect transistors.
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) | 1978-06-23 | 1978-12-23 | 1979-06-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-23 | 1982-12-23 | 1983-06-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-23 | 1986-12-23 | 1987-06-24 | $7700.00 | Window Closed / Lapsed |