Patent US3764922A successfully refreshed from Google Patents.
US3764922A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Amplifier offset compensation arrangement
Assignee: Reliance Electric Co
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Filing: 1971-10-14
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Granted: 1973-10-09
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Expires: 1991-10-14
Abstract
Abstract Different analog signals are successively connected to an amplifier, which may have a variable gain controlled by a digital computer, for example. When each analog signal is to be connected to the amplifier, the amplifier is first switched into a stabilizing mode in a closed-loop with an integrator so that the integrator charges up to a value commensurate with the offset voltage of the amplifier. The integrator output is then connected to the variable-gain amplifier during an immediately-following measurement mode to compensate for the amplifier offset.
Inventors
- 👤 E Gilbert
- 👤 T Oliver
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 10:05
CPC Classifications
H; H03; H03G; H03G1/00; H03G1/0005; H03G1/0088; H03F; H03F3/00; H03F3/38; H03F3/387; H03F3/393
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
179 words
A signal-processing device for selectively applying a plurality of analog input signals to an output device with selected gains, comprising, in combination: a first amplifier having a negative feedback circuit; means for varying said feedback circuit to vary the overall gain of said first Amplifier; an integrator circuit; first switching means for sequentially connecting said first amplifier and said integrator circuit in first and second modes, said first switching means being operable in said first mode to connect said first amplifier and said integrator circuit in a degenerative closed loop to cause said integrator circuit to charge to a steady-state output signal level commensurate with any offset voltage existing in said first amplifier, and operable in said second mode to disable said integrator circuit, apply said steady-state output signal to said first amplifier to compensate for said offset voltage, and apply a selected one of said analog input signals to said first amplifier; and second switching means for connecting the output of said first amplifier to said output device while said first amplifier is connected in said second mode.
Claim 2
Dependent Claim
179 words
A signal-processing device for selectively applying a plurality of analog input signals to an output device with selected gains, comprising, in combination: a first amplifier having a negative feedback circuit; means for varying said feedback circuit to vary the overall gain of said first Amplifier; an integrator circuit; first switching means for sequentially connecting said first amplifier and said integrator circuit in first and second modes, said first switching means being operable in said first mode to connect said first amplifier and said integrator circuit in a degenerative closed loop to cause said integrator circuit to charge to a steady-state output signal level commensurate with any offset voltage existing in said first amplifier, and operable in said second mode to disable said integrator circuit, apply said steady-state output signal to said first amplifier to compensate for said offset voltage, and apply a selected one of said analog input signals to said first amplifier; and second switching means for connecting the output of said first amplifier to said output device while said first amplifier is connected in said second mode.
Claim 3
Dependent Claim
17 words
A device according to claim 1 wherein said integrator circuit comprises a second amplifier and a capacitor.
Claim 4
Dependent Claim
74 words
A device according to claim 1 wherein said first amplifier has a differential input circuit including first and second input terminals, said negative feedback circuit of said first amplifier being connected between the output terminal of said first amplifier and the first of said input terminals, and said first switching means being operable to connect said selected one of said analog input signals to the second of said input terminals during said second mode.
Claim 5
Dependent Claim
39 words
A device according to claim 1 wherein said first switching means is operable during said second mode to apply said steady-state output signal and said selected one of said analog input signals connected in series to said first amplifier.
Claim 6
Dependent Claim
50 words
A device according to claim 1 wherein said first switching means is operable during said second mode to apply said selected one of said analog input signals to a first stage of said first amplifier and to apply said steady-state output signal to a different stage of said first amplifier.
Claim 7
Dependent Claim
68 words
A device according to claim 1 having a floating source for providing said selected one of said analog input signals, said first amplifier having an input circuit including first and second input terminals, one side of said source being connected to said first input terminal, said first switching means being operable during said second mode to connect said steady-state output signal to the other side of said source.
Claim 8
Dependent Claim
93 words
A device according to claim 1 having a source for providing said selected one of said analog input signals, said first amplifier comprising a plurality of cascaded amplifying stages including a first stage having first and second input terminals and further stages, one side of said source being connected to one of said input terminals, said first switching means being operable during said second mode to connect the other side of said source to the other of said input terminals and to apply said steady-state output signal to one of said further stages.
Claim 9
Dependent Claim
160 words
Apparatus for selectively connecting individual ones of a group of analog input signals to a signal-processing device through a controllable-gain amplifier which is subject to drift, comprising, in combination: first selective switching means operable over a first-time interval to selectively connect an individual one of said input signals to said amplifier; second selective switching means operable to control the gain of said amplifier; offset voltage measuring means controllable by third switching means to derive a compensating signal commensurate with the offset of said amplifier; fourth switching means operable to apply said compensating signal to said amplifier to compensate for said drift; timing means; computer means for applying signals to simultaneously operate said first and second selective switching means and said timing means, said timing means being operative to operate said third switching means for a first predetermined time period extending beyond said first time interval and then operative to disable said third switching means and Enable said fourth switching means.
Claim 10
Dependent Claim
160 words
Apparatus for selectively connecting individual ones of a group of analog input signals to a signal-processing device through a controllable-gain amplifier which is subject to drift, comprising, in combination: first selective switching means operable over a first-time interval to selectively connect an individual one of said input signals to said amplifier; second selective switching means operable to control the gain of said amplifier; offset voltage measuring means controllable by third switching means to derive a compensating signal commensurate with the offset of said amplifier; fourth switching means operable to apply said compensating signal to said amplifier to compensate for said drift; timing means; computer means for applying signals to simultaneously operate said first and second selective switching means and said timing means, said timing means being operative to operate said third switching means for a first predetermined time period extending beyond said first time interval and then operative to disable said third switching means and Enable said fourth switching means.
References Cited (Backward Citations)
US3200338A
Cited
US3654560A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-08 | 1977-04-09 | 1977-10-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-08 | 1981-04-09 | 1981-10-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-08 | 1985-04-09 | 1985-10-09 | $7700.00 | Window Closed / Lapsed |