Patent US4870367A successfully refreshed from Google Patents.
US4870367A
Expired / Lapsed
US
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Signal amplifier circuit
Assignee: Alps Alpine Co Ltd
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Filing: 1988-08-01
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Granted: 1989-09-26
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Expires: 2008-08-01
Abstract
Abstract A signal amplifier circuit which can amplify, with a simple construction, an AC component having an amplitude of one polarity with accuracy from a composite signal which contains a DC component combined with the AC component. The circuit comprises a comparing amplifier circuit connected to receive such a composite signal at an input terminal thereof via a capacitor, means connected to the other input terminal of the comparing amplifier circuit for providing a reference voltage to the latter, and a clamping circuit for clamping the signal which has passed the capacitor to the reference voltage.
Inventors
- 👤 Kouji Nakase
- 👤 Kazuo Hasegawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:20
CPC Classifications
H; H03; H03K; H03K5/00; H03K5/01; H03K5/08; H03K5/082; H03K5/086; H03K5/003
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
174 words
A signal processing circuit for processing a unipolar AC component which is small in amplitude in relation to, and is superimposed on, a DC component of an input signal, comprising: a capacitor having one end connected to receive said input signal for removing said DC component and outputting at its other end a signal of only said AC component; a reference voltage providing means for supplying a reference voltage signal; a clamping circuit for clamping a peak voltage of said AC component to said reference voltage signal; and a comparing amplifier having a first terminal connected via a current limiting resistor to said other end of said capacitor for receiving and amplifying said AC component signal clamped to said reference voltage signal, and having a second terminal for receiving said reference voltage signal, said comparing amplifier having connected between its output terminal and its inverting input terminal a feedback resistor, which, in conjunction with said current limiting resistor, caused said comparing amplifier to amplify said clamped AC component signal without distortion for further processing.
Claim 2
Dependent Claim
174 words
A signal processing circuit for processing a unipolar AC component which is small in amplitude in relation to, and is superimposed on, a DC component of an input signal, comprising: a capacitor having one end connected to receive said input signal for removing said DC component and outputting at its other end a signal of only said AC component; a reference voltage providing means for supplying a reference voltage signal; a clamping circuit for clamping a peak voltage of said AC component to said reference voltage signal; and a comparing amplifier having a first terminal connected via a current limiting resistor to said other end of said capacitor for receiving and amplifying said AC component signal clamped to said reference voltage signal, and having a second terminal for receiving said reference voltage signal, said comparing amplifier having connected between its output terminal and its inverting input terminal a feedback resistor, which, in conjunction with said current limiting resistor, caused said comparing amplifier to amplify said clamped AC component signal without distortion for further processing.
Claim 3
Dependent Claim
31 words
The signal processing circuit of claim 1 wherein said first terminal of said comparing amplifier is said inverting terminal, and said second terminal of said comparing amplifier is a noninverting terminal.
Claim 4
Dependent Claim
35 words
The signal processing circuit of claim 1 wherein said clamping circuit comprises a diode having an anode connected to said other end of said capacitor and a cathode connected to receive said reference voltage signal.
Claim 5
Dependent Claim
68 words
The signal processing circuit of claim 1 wherein said clamping circuit comprises a second comparing amplifier having a noninverting terminal coupled to receive said reference voltage signal and an inverting terminal coupled to said other end of said capacitor, with an output terminal coupled to a cathode of a second diode, wherein an anode of said second diode is also coupled to said other end of said capacitor.
Claim 6
Dependent Claim
23 words
The signal processing circuit of claim 1 wherein said further processing includes converting said amplified clamped AC component signal to a binary waveform.
Claim 7
Dependent Claim
23 words
The signal processing circuit of claim 2 wherein said further processing includes converting said amplified clamped AC component signal to a binary waveform.
Claim 8
Dependent Claim
23 words
The signal processing circuit of claim 3 wherein said further processing includes converting said amplified clamped AC component signal to a binary waveform.
Claim 9
Dependent Claim
23 words
The signal processing circuit of claim 4 wherein said further processing includes converting said amplified clamped AC component signal to a binary waveform.
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) | 1992-09-25 | 1993-03-27 | 1993-09-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-09-25 | 1997-03-27 | 1997-09-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-09-25 | 2001-03-27 | 2001-09-26 | $7700.00 | Window Closed / Lapsed |