Patent US3633005A successfully refreshed from Google Patents.
US3633005A
Expired / Lapsed
US
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A four quadrant multiplier using a single amplifier in a balanced modulator circuit
Assignee: International Business Machines Corp
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Filing: 1970-02-26
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Granted: 1972-01-04
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Expires: 1990-02-26
Abstract
Abstract A multiplier circuit, having a relatively constant input impedance, capable of multiplying a positive or a negative input signal by a gain which is variable from a positive to a negative value by varying one control impedance. The input signal is applied to a reference input and to a signal input which includes a feedback path to provide both positive and negative products without the need for additional sign circuits or complimentary signals. The multiplier circuit can be adapted for use as a balanced modulator by providing an analog input signal and switching the control impedance between two different impedance values with a binary carrier signal.
Inventors
- 👤 Howard N Leighton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 05:51
CPC Classifications
G; G06; G06J; G06J1/00; H; H03; H03C; H03C1/00; H03C1/52; H03C1/54; H03C1/542; H03C1/545; H03F; H03F3/00; H03F3/72; H03K; H03K7/00; H03K7/02
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
107 words
A multiplier comprising: operational amplifier means having a first and a second input terminal and an output terminal; signal input means connected to a first terminal of a reference input impedance and to a first terminal of an input impedance; reference impedance means connected between said first input terminal and a ground reference potential; said reference input impedance and said input impedance each having a second terminal connected to said first and second input terminals respectively; feedback impedance means connected between said output terminal and said second input terminal; variable-impedance means connected between said second input terminal and ground for controlling the gain of said operational amplifier.
Claim 2
Dependent Claim
107 words
A multiplier comprising: operational amplifier means having a first and a second input terminal and an output terminal; signal input means connected to a first terminal of a reference input impedance and to a first terminal of an input impedance; reference impedance means connected between said first input terminal and a ground reference potential; said reference input impedance and said input impedance each having a second terminal connected to said first and second input terminals respectively; feedback impedance means connected between said output terminal and said second input terminal; variable-impedance means connected between said second input terminal and ground for controlling the gain of said operational amplifier.
Claim 3
Dependent Claim
34 words
The multiplier as defined in claim 1 wherein said bias impedance means and said first impedance means are of equal value; and said first impedance means is one-half the value of said feedback impedance.
Claim 4
Dependent Claim
26 words
The multiplier as defined in claim 2 wherein said variable-impedance control means is variable between the values of one-half the feedback impedance to an infinite impedance.
Claim 5
Dependent Claim
25 words
The multiplier of claim 3 further comprising control means for switching said variable control impedance in response to the condition of a binary input signal.
Claim 6
Dependent Claim
91 words
The multiplier of claim 1 wherein said variable control impedance comprises: a plurality of digital input terminals for accepting a binary word, a plurality of switching means each connected to one of said digital input terminals; a plurality of gain control resistors each connected to a separate one of said switching means; said plurality of gain control resistors connected to said second input terminal; whereby said switch means selectively engages combinations of said gain control resistors to said second input terminal so as to control the gain of said operational amplifier.
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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) | 1975-01-03 | 1975-07-05 | 1976-01-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-03 | 1979-07-05 | 1980-01-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-03 | 1983-07-05 | 1984-01-04 | $7700.00 | Window Closed / Lapsed |