US4074204A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Equalizing amplifier
Assignee: VAN ALSTINE AUDIO SYSTEMS Inc
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Filing: 1976-11-22
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Granted: 1978-02-14
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Expires: 1996-11-22
Abstract
Abstract A fully passive frequency contouring amplifier using segregated passive networks to shape the different portions of the signal thus avoiding all phase distortion and permitting the stages to be coupled without coupling capacitors, thus avoiding distortion caused by the nonlinearities of capacitors. In addition, a special DC servo loop is used to drastically reduce DC amplification.
Inventors
- 👤 Gregory W. Broburg
- 👤 Allen C. Clark
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 06:11
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/34
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
179 words
A frequency contouring amplifier comprising: a first amplifying means having an input connected to receive the signal and having an output, said first amplifying means increasing the entire spectrum of the signal; a first passive filter network connected to the output of said first amplifying means so as to attenuate the portion of the signal above 2122 Hertz; a second amplifying means having an input connected to the output of said amplifying means and having an output, said second amplifying means increasing the entire spectrum of the signal received from said first amplifying means as attenuated by said first filter network; a second passive filter network connected to the output of said second amplifying means so as to attenuate the portion of the signal from 50 to 500 Hertz; and at least one third amplifying means connected to the output of the second amplifying means to produce a low impedance frequency contoured output signal, said third amplifying means increasing the entire spectrum of the signal received from said second amplifying means as attenuated by said second passive filter network.
Claim 2
Dependent Claim
179 words
A frequency contouring amplifier comprising: a first amplifying means having an input connected to receive the signal and having an output, said first amplifying means increasing the entire spectrum of the signal; a first passive filter network connected to the output of said first amplifying means so as to attenuate the portion of the signal above 2122 Hertz; a second amplifying means having an input connected to the output of said amplifying means and having an output, said second amplifying means increasing the entire spectrum of the signal received from said first amplifying means as attenuated by said first filter network; a second passive filter network connected to the output of said second amplifying means so as to attenuate the portion of the signal from 50 to 500 Hertz; and at least one third amplifying means connected to the output of the second amplifying means to produce a low impedance frequency contoured output signal, said third amplifying means increasing the entire spectrum of the signal received from said second amplifying means as attenuated by said second passive filter network.
Claim 3
Dependent Claim
20 words
The circuit of claim 1 in which said amplifying means are connected together output to input only by resistive means.
Claim 4
Dependent Claim
45 words
The circuit of claim 2 including an automatic multistage DC coupled servo loop from the output of the last amplifying means to the input of said first amplifying means which servo loop includes a third passive filter means to attenuate most of the AC signal.
Claim 5
Dependent Claim
13 words
The circuit of claim 2 in which said amplifying means comprise operational amplifiers.
Claim 6
Dependent Claim
13 words
The circuit of claim 3 in which said amplifying means comprise operational amplifiers.
Claim 7
Dependent Claim
17 words
The circuit of claim 4 including purely resistive feedback circuits for controlling the gain of the amplifiers.
Claim 8
Dependent Claim
17 words
The circuit of claim 5 including purely resistive feedback circuits for controlling the gain of the amplifiers.
References Cited (Backward Citations)
US3863173A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-02-13 | 1981-08-15 | 1982-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-13 | 1985-08-15 | 1986-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-13 | 1989-08-15 | 1990-02-14 | $7700.00 | Window Closed / Lapsed |