Patent US3958185A successfully refreshed from Google Patents.
US3958185A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low noise amplifier
Assignee: International Business Machines Corp
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Filing: 1975-06-26
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Granted: 1976-05-18
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Expires: 1995-06-26
Abstract
Abstract An amplifier particularly suited for use as a sense amplifier for the detection of magnetic bubble domains in a magnetic bubble chip. A feedback loop is used to reduce D.C. offset of the input and output signals. Noise unavoidably introduced into the feedback loop is cancelled upon input of the feedback signal into the amplifier. The noise cancellation is effected by the introduction into the amplifier input of another noise signal of equal magnitude and opposite polarity provided by another noise pickup loop separate from the feedback loop.
Inventors
- 👤 Joseph Charles Hartung
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 10:43
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/26; H03F2200/00; H03F2200/372
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
73 words
An amplification system comprising: a first amplifier having an input and an output; feedback means connecting said output to said input for reduction of D.C. offset of an output signal of said first amplifier, said feedback means introducing external noise into said input; and noise cancellation means connected to said input for cancelling noise introduced by said feedback means by introduction into said input of additional noise of equal magnitude and opposite polarity.
Claim 2
Dependent Claim
73 words
An amplification system comprising: a first amplifier having an input and an output; feedback means connecting said output to said input for reduction of D.C. offset of an output signal of said first amplifier, said feedback means introducing external noise into said input; and noise cancellation means connected to said input for cancelling noise introduced by said feedback means by introduction into said input of additional noise of equal magnitude and opposite polarity.
Claim 3
Dependent Claim
41 words
The amplification system of claim 1 further comprising an input signal means for providing a signal to said input of said first amplifier for amplification, said noise cancellation means connecting said input signal means to said input of said first amplifier.
Claim 4
Dependent Claim
36 words
The amplification system of claim 2 wherein said feedback means includes a second amplifier having an output connected to said input of said first amplifier and an input connected to said output of said first amplifier.
Claim 5
Dependent Claim
47 words
The amplification system of claim 3 wherein said external noise is introduced into said input by a conductive means connected to said feedback means and said noise cancellation means further comprises another conductive means oriented 180° with respect to said conductive means connected to said feedback means.
Claim 6
Dependent Claim
27 words
The amplification system of claim 4 wherein said first amplifier and said second amplifier are differential amplifiers and said second amplifier is connected as an inverting amplifier.
Claim 7
Dependent Claim
22 words
The amplification system of claim 5 wherein said input signal means comprises a magnetoresistive sensor connected in parallel with a current source.
Claim 8
Dependent Claim
47 words
The amplification system of claim 3 wherein said external noise is introduced into said input by a conductive means connected to said feedback means and said noise cancellation means further comprises another conductive means oriented 0° with respect to said conductive means connected to said feedback means.
Claim 9
Dependent Claim
37 words
The amplification system of claim 7 wherein said first amplifier and said second amplifier are differential amplifiers and said second amplifier is connected as a noninverting amplifier, and said first amplifier is connected as an inverting amplifier.
Claim 10
Dependent Claim
22 words
The amplification system of claim 8 wherein said input signal means comprises a magnetoresistive sensor connected in parallel with a current source.
References Cited (Backward Citations)
US3740659A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-05-18 | 1979-11-17 | 1980-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-18 | 1983-11-17 | 1984-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-18 | 1987-11-17 | 1988-05-18 | $7700.00 | Window Closed / Lapsed |