US3781869A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transducer amplifier with automatic balance
Assignee: INSERVCO Inc
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Filing: 1972-03-20
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Granted: 1973-12-25
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Expires: 1992-03-20
Abstract
Abstract An amplifier for strain gages and other transducers in quarter, half or full bridge configurations provides an analog output suited for measurement, control or display purposes. The amplifier includes temperature compensation and automatic zero balance, the former realized from the voltage-temperature characteristic of a silicon PN junction used to affect the offset of an integrated circuit amplifier stage. The signal for zero balance is derived from the amplifier output, sampled and retained in an analog to digital converter and reconverted to analog form for application to a stage of the amplifier in opposition to the measurement signal, resetting for zero balance being under manual control.
Inventors
- 👤 D Sudnick
- 👤 R Shutts
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 20:25
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/34; H03F3/343; H03F3/347; H03F1/00; H03F1/30
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
187 words
A transducer amplifier having automatic self correction relative to a selected input signal from the transducer, comprising: a. an amplifier stage, said amplifier stage having a first input adapted for receipt of a signal from the transducer, said amplifier stage having a second input adapted for receipt of a correction signal, and said amplifier stage providing an output signal proportional to the difference between such input signals, b. switching means for permitting input of said correction signal to said second input of said amplifier stage and for temporarily eliminating input of said correction signal to said second input of said amplifier stage, whereby when said correction signal is temporarily eliminated from said amplifier stage, a conditional output signal proportionally representative to said signal from said transducer is provided from said amplifier stage, c. means for retaining a signal proportionally representative to said conditional output signal and for continuously applying same as said correction signal to said switching means for selective application to second input of said amplifier stage, d. whereby said output signal from said amplifier stage is referenced to a selected input signal from the transducer.
Claim 2
Dependent Claim
187 words
A transducer amplifier having automatic self correction relative to a selected input signal from the transducer, comprising: a. an amplifier stage, said amplifier stage having a first input adapted for receipt of a signal from the transducer, said amplifier stage having a second input adapted for receipt of a correction signal, and said amplifier stage providing an output signal proportional to the difference between such input signals, b. switching means for permitting input of said correction signal to said second input of said amplifier stage and for temporarily eliminating input of said correction signal to said second input of said amplifier stage, whereby when said correction signal is temporarily eliminated from said amplifier stage, a conditional output signal proportionally representative to said signal from said transducer is provided from said amplifier stage, c. means for retaining a signal proportionally representative to said conditional output signal and for continuously applying same as said correction signal to said switching means for selective application to second input of said amplifier stage, d. whereby said output signal from said amplifier stage is referenced to a selected input signal from the transducer.
Claim 3
Dependent Claim
42 words
A transducer amplifier having automatic self correction relative to a selected input signal from the transducer as set forth in claim 1, wherein said switching means comprises: means for actuating said retaining means in correspondence with the elimination of said correction signal.
Claim 4
Dependent Claim
49 words
A transducer amplifier having automatic self correction relative to a selected input signal from the transducer as set forth in claim 2, wherein said retaining means comprises: digital memory means having capability for accurately maintaining said signal proportionally representative to said conditional output signal over long intervals of time.
Claim 5
Dependent Claim
83 words
A transducer amplifier having automatic self correction relative to a selected input signal from the transducer as set forth in claim 3, wherein said retaining means further includes: a multiplier stage for boosting said conditional output signal level, an analog to digital converter for applying such boosted conditional output signal to said digital memory, and a divider interconnected between said digital memory and said second input of said amplifier stage for dividing the output signal from the former before application to the latter.
Claim 6
Dependent Claim
51 words
A transducer amplifier having automatic self correction relative to a selected input signal from the transducer as set forth in claim 4, wherein said switching means comprises: a delayed pulse generator operative to actuate said digital memory a predetermined interval after eliminating said correction signal from application to said amplifier stage.
Claim 7
Dependent Claim
52 words
A transducer amplifier having automatic self correction relative to a selected input signal from the transducer as set forth in claim 4, wherein said amplifier stage comprises a unity gain differential input amplifier, and said divider comprises an adjustable divider circuit to provide the reciprocal of the gain of said multiplier stage.
Claim 8
Dependent Claim
165 words
Apparatus for amplifying the variations of an analog input signal from a balance level, comprising: a. an amplifier, b. said amplifier having a first input for receipt of said analog input signal, c. said amplifier having a second input, d. means for connecting said second input of said amplifier for selective receipt of a reference signal and a balance signal, e. means for supplying said balance signal derived from said analog input signal by said amplifier to said connecting means, f. said supplying means comprising means for retaining a signal proportionally representative to said balance signal in digital format, g. said connecting means comprising means for selectively switching said second input of said amplifier between a reference connection for development of said balance signal and a connection to said supplying means, h. said retaining means being responsive to said switching means for storing a new signal proportionally representative to said balance signal when said second input of said amplifier is connected to said reference connection.
Claim 9
Dependent Claim
165 words
Apparatus for amplifying the variations of an analog input signal from a balance level, comprising: a. an amplifier, b. said amplifier having a first input for receipt of said analog input signal, c. said amplifier having a second input, d. means for connecting said second input of said amplifier for selective receipt of a reference signal and a balance signal, e. means for supplying said balance signal derived from said analog input signal by said amplifier to said connecting means, f. said supplying means comprising means for retaining a signal proportionally representative to said balance signal in digital format, g. said connecting means comprising means for selectively switching said second input of said amplifier between a reference connection for development of said balance signal and a connection to said supplying means, h. said retaining means being responsive to said switching means for storing a new signal proportionally representative to said balance signal when said second input of said amplifier is connected to said reference connection.
Claim 10
Dependent Claim
29 words
Apparatus for amplifying the variations of an analog input signal from a balance level as set forth in claim 7, wherein said reference connection comprises: a grounded reference connection.
Claim 11
Dependent Claim
75 words
Apparatus for amplifying the variations of an analog input signal from a balance level as set forth in claim 7, wherein said retaining means comprises an analog to digital converter, said supplying means further comprises a multiplier for modifying the output of said amplifier, means for converting the signal stored in said retaining means to analog format, and a divider for reducing such analog format signal for application to said second input of said amplifier.
Claim 12
Dependent Claim
57 words
Apparatus for amplifying the variations of an analog input signal from a balance level as set forth in claim 9, wherein said multiplier comprises a furtHer amplifier and said divider comprises an impedance network for reducing the signal from said converting means by a factor substantially equal to the reciprocal of the gain of said further amplifier.
Claim 13
Dependent Claim
37 words
Apparatus for amplifying the variations of an analog input signal from a balance level as set forth in claim 10, wherein said converting means comprises: a digital to analog converter compatible with said analog to digital converter.
Claim 14
Dependent Claim
43 words
Apparatus for amplifying the variations of an analog input signal from a balance level as set forth in claim 11, wherein said amplifier comprises: a unity gain amplifier and a power amplifier for supplying a signal to said further amplifier of said multiplier.
Claim 15
Dependent Claim
84 words
Apparatus for amplifying the variations of an analog input signal from a balance level as set forth in claim 7, further including: a second amplifier for said input signal, said second amplifier having an output connected to the first input of said first mentioned amplifier, a silicon diode, and means for monitoring the voltage change in said silicon diode as a function of temperature and for generating a compensation signal for application to said second amplifier to compensate for temperature variations of the latter.
Claim 16
Dependent Claim
40 words
Apparatus for amplifying the variations of an analog input signal from a balance level as set forth in claim 13, wherein said second amplifier comprises: an integrated circuit amplifier, said compensation signal being applied to modify the offset of same.
Claim 17
Dependent Claim
39 words
Apparatus for amplifying the variations of an analog input signal from a balance level as set forth in claim 14, wherein said second amplifier includes: first and second inputs adapted for receipt of a signal from a bridge network.
Claim 18
Dependent Claim
127 words
Apparatus for stabilizing an amplifier subject to drift due to temperature variations, comprising: a. an integrated circuit amplifier, said integrated circuit amplifier having an offset circuit, b. means forming a PN junction, said PN junction having a temperature characteristic whereby the voltage drop across said PN junction varies with the temperature thereof, c. means for developing a voltage across said PN junction, said voltage being dependent upon the temperature characteristic of said PN junction, d. means for converting said voltage to a compensation signal, e. means for applying said compensation signal to said integrated circuit and amplifier in a manner to stabilize said amplifier drift, and, f. said means for applying comprising means for applying said compensation signal to modify the offset of said integrated circuit amplifier.
Claim 19
Dependent Claim
127 words
Apparatus for stabilizing an amplifier subject to drift due to temperature variations, comprising: a. an integrated circuit amplifier, said integrated circuit amplifier having an offset circuit, b. means forming a PN junction, said PN junction having a temperature characteristic whereby the voltage drop across said PN junction varies with the temperature thereof, c. means for developing a voltage across said PN junction, said voltage being dependent upon the temperature characteristic of said PN junction, d. means for converting said voltage to a compensation signal, e. means for applying said compensation signal to said integrated circuit and amplifier in a manner to stabilize said amplifier drift, and, f. said means for applying comprising means for applying said compensation signal to modify the offset of said integrated circuit amplifier.
Claim 20
Dependent Claim
110 words
Apparatus for stabilizing an amplifier subject to drift due to temperature variations, comprising: a. means forming a PN junction, said PN junction having a temperature characteristic whereby the voltage drop across such PN junction varies with the temperature thereof, b. means for developing a voltage across said PN junction, said voltage being dependent upon the temperature characteristic of said PN junction, c. means for converting said voltage to a compensation signal, d. means for applying said compensation signal to said amplifier in a manner to stabilize said amplifier drift, and, e. said converting means comprising an integrated circuit amplifier having adjustable gain for modifying the amplitude of said compensation signal.
Claim 21
Dependent Claim
110 words
Apparatus for stabilizing an amplifier subject to drift due to temperature variations, comprising: a. means forming a PN junction, said PN junction having a temperature characteristic whereby the voltage drop across such PN junction varies with the temperature thereof, b. means for developing a voltage across said PN junction, said voltage being dependent upon the temperature characteristic of said PN junction, c. means for converting said voltage to a compensation signal, d. means for applying said compensation signal to said amplifier in a manner to stabilize said amplifier drift, and, e. said converting means comprising an integrated circuit amplifier having adjustable gain for modifying the amplitude of said compensation signal.
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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) | 1976-12-24 | 1977-06-25 | 1977-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-24 | 1981-06-25 | 1981-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-24 | 1985-06-25 | 1985-12-25 | $7700.00 | Window Closed / Lapsed |