US3715680A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Active rc loss equalizer
Assignee: AT&T Inc
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Filing: 1971-07-29
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Granted: 1973-02-06
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Expires: 1991-07-29
Abstract
Abstract An active resistance-capacitance (RC) loss equalizer circuit which provides a second order ''''bump'''' in the frequency domain is disclosed. The bump height, bump width, and bump center frequency are independently adjustable by sliding switches which alter predetermined circuit resistor values. The equalizer circuit is preferably realized using operational amplifiers bonded to a thin film circuit substrate.
Inventors
- 👤 P Fleischer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 19:57
CPC Classifications
H; H03; H03H; H03H11/00; H03H11/02; H03H11/04; H03H11/12; H03H11/1217; H03H11/1252; H04; H04B; H04B3/00; H04B3/02; H04B3/04; H04B3/14; H04B3/141
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
161 words
Active RC adjustable loss equalizer apparatus having an input terminal and an output terminal comprising: a first feedback amplifier having an input and output; a first adjustable resistive T-network connecting said equalizer input terminal to the input and output of said first amplifier; a second feedback amplifier having an input and output, said input resistively connected to the output of said first amplifier; a third feedback amplifier having an input and output, said output resistively connected to the input of said first amplifier; a second adjustable resistive T-network connecting the output of said second amplifier and the input of said third amplifier; a fourth feedback amplifier having an input and output, said output connected to said equalizer output terminal; a third adjustable resistive T-network connecting thE output of said second amplifier and the input of said fourth amplifier; and resistive circuit means coupling said equalizer input terminal, and the output of said first amplifier, to the input of said fourth amplifier.
Claim 2
Dependent Claim
161 words
Active RC adjustable loss equalizer apparatus having an input terminal and an output terminal comprising: a first feedback amplifier having an input and output; a first adjustable resistive T-network connecting said equalizer input terminal to the input and output of said first amplifier; a second feedback amplifier having an input and output, said input resistively connected to the output of said first amplifier; a third feedback amplifier having an input and output, said output resistively connected to the input of said first amplifier; a second adjustable resistive T-network connecting the output of said second amplifier and the input of said third amplifier; a fourth feedback amplifier having an input and output, said output connected to said equalizer output terminal; a third adjustable resistive T-network connecting thE output of said second amplifier and the input of said fourth amplifier; and resistive circuit means coupling said equalizer input terminal, and the output of said first amplifier, to the input of said fourth amplifier.
Claim 3
Dependent Claim
161 words
Active RC adjustable loss equalizer apparatus having an input terminal and an output terminal comprising: a first feedback amplifier having an input and output; a first adjustable resistive T-network connecting said equalizer input terminal to the input and output of said first amplifier; a second feedback amplifier having an input and output, said input resistively connected to the output of said first amplifier; a third feedback amplifier having an input and output, said output resistively connected to the input of said first amplifier; a second adjustable resistive T-network connecting the output of said second amplifier and the input of said third amplifier; a fourth feedback amplifier having an input and output, said output connected to said equalizer output terminal; a third adjustable resistive T-network connecting thE output of said second amplifier and the input of said fourth amplifier; and resistive circuit means coupling said equalizer input terminal, and the output of said first amplifier, to the input of said fourth amplifier.
Claim 4
Dependent Claim
161 words
Active RC adjustable loss equalizer apparatus having an input terminal and an output terminal comprising: a first feedback amplifier having an input and output; a first adjustable resistive T-network connecting said equalizer input terminal to the input and output of said first amplifier; a second feedback amplifier having an input and output, said input resistively connected to the output of said first amplifier; a third feedback amplifier having an input and output, said output resistively connected to the input of said first amplifier; a second adjustable resistive T-network connecting the output of said second amplifier and the input of said third amplifier; a fourth feedback amplifier having an input and output, said output connected to said equalizer output terminal; a third adjustable resistive T-network connecting thE output of said second amplifier and the input of said fourth amplifier; and resistive circuit means coupling said equalizer input terminal, and the output of said first amplifier, to the input of said fourth amplifier.
Claim 5
Dependent Claim
35 words
The equalizer as defined in claim 1 wherein at least one of said resistive T-networks further comprises: a first fixed resistive leg; a second slideably adjustable resistive leg; and a third slideably adjustable resistive leg.
Claim 6
Dependent Claim
23 words
The equalizer as defined in claim 1 wherein at least one of said adjustable resistive T-networks exhibits a geometric variation in effective resistance.
Claim 7
Dependent Claim
185 words
Active RC adjustable loss equalizer apparatus having an input terminal and an output terminal comprising: a first operational amplifier having feedback means connected between said amplifier''s input and output; a first slideably adjustable resistive T-network connecting said equalizer input terminal to the input and output of said first operational amplifier; a second operational amplifier having feedback means connected between said amplifier''s input and output, said input resistively connected to the output of said first amplifier; a third operational amplifier having feedback means connected between said amplifier''s input and output, said output resistively connected to the input of said first amplifier; a second slideably adjustable resistive T-network connecting the output of said second amplifier and the input of said third amplifier; a fourth operational amplifier having feedback means connected between said amplifier''s input and output, said output connected to said equalizer output terminal; a third slideably adjustable resistive T-network connecting the output of said second amplifier and the input of said fourth amplifier; and resistive circuit means coupling said equalizer input terminal, and the output of said first amplifier, to the input of said fourth amplifier.
Claim 8
Dependent Claim
185 words
Active RC adjustable loss equalizer apparatus having an input terminal and an output terminal comprising: a first operational amplifier having feedback means connected between said amplifier''s input and output; a first slideably adjustable resistive T-network connecting said equalizer input terminal to the input and output of said first operational amplifier; a second operational amplifier having feedback means connected between said amplifier''s input and output, said input resistively connected to the output of said first amplifier; a third operational amplifier having feedback means connected between said amplifier''s input and output, said output resistively connected to the input of said first amplifier; a second slideably adjustable resistive T-network connecting the output of said second amplifier and the input of said third amplifier; a fourth operational amplifier having feedback means connected between said amplifier''s input and output, said output connected to said equalizer output terminal; a third slideably adjustable resistive T-network connecting the output of said second amplifier and the input of said fourth amplifier; and resistive circuit means coupling said equalizer input terminal, and the output of said first amplifier, to the input of said fourth amplifier.
Claim 9
Dependent Claim
35 words
The equalizer as defined in claim 4 wherein at least one of said resistive T-networks further comprises: a first fixed resistive leg; a second slideably adjustable resistive leg; and a third slideably adjustable resistive leg.
Claim 10
Dependent Claim
23 words
The equalizer as defined in claim 4 wherein at least one of said adjustable resistive networks exhibits a geometric variation in effective resistance.
Claim 11
Dependent Claim
143 words
An adjustable loss equalizer having first, second, third, and fourth feedback operational amplifiers, an input terminal and an output terminal, comprising: a first adjustable resistive T-network connecting said input terminal and the input and output of said first amplifier; a second adjustable resistive T-network connecting the output of said second amplifier and the input of said third amplifier, the input of said second amplifier resistively connected to the output of said first amplifier, and the output of said third amplifier resistively connected to the input of said first amplifier; a third adjustable resistive T-network connecting the output of said second amplifier and the input of said fourth amplifier, the output of said fourth amplifier connected to said output terminal; and first resistive circuit means connecting said equalizer input terminal, and the output of said first amplifier, to the input of said fourth amplifier.
Claim 12
Dependent Claim
143 words
An adjustable loss equalizer having first, second, third, and fourth feedback operational amplifiers, an input terminal and an output terminal, comprising: a first adjustable resistive T-network connecting said input terminal and the input and output of said first amplifier; a second adjustable resistive T-network connecting the output of said second amplifier and the input of said third amplifier, the input of said second amplifier resistively connected to the output of said first amplifier, and the output of said third amplifier resistively connected to the input of said first amplifier; a third adjustable resistive T-network connecting the output of said second amplifier and the input of said fourth amplifier, the output of said fourth amplifier connected to said output terminal; and first resistive circuit means connecting said equalizer input terminal, and the output of said first amplifier, to the input of said fourth amplifier.
Claim 13
Dependent Claim
35 words
The equalizer as defined in claim 7 wherein at least one of said resistive T-networks further comprises: a first fixed resistive leg; a second slideably adjustable resistive leg; and a third slideably adjustable resistive leg.
Claim 14
Dependent Claim
23 words
The equalizer as defined in claim 8 wherein at least one of said adjustable resistive T-networks exhibits a geometric variation in effective resistance.
Claim 15
Dependent Claim
147 words
An adjustable loss equalizer having first, second, third, and fourth feedback amplifiers, an input terminal and an output terminal, comprising: a first slideably adjustable resistive T-network connecting said input terminal and the input And output of said first amplifier; a second slideably adjustable resistive T-network connecting the output of said second amplifier and the input of said third amplifier, the input of said second amplifier resistively connected to the output of said first amplifier; a third slideably adjustable resistive T-network connecting the output of said second amplifier and the input of said fourth amplifier, the output of said fourth amplifier connected to said output terminal; first resistive circuit means connecting said equalizer input terminal, and the output of said first amplifier, to the input of said fourth amplifier; and second resistive circuit means connecting the output of said third amplifier and the input of said first amplifier.
Claim 16
Dependent Claim
147 words
An adjustable loss equalizer having first, second, third, and fourth feedback amplifiers, an input terminal and an output terminal, comprising: a first slideably adjustable resistive T-network connecting said input terminal and the input And output of said first amplifier; a second slideably adjustable resistive T-network connecting the output of said second amplifier and the input of said third amplifier, the input of said second amplifier resistively connected to the output of said first amplifier; a third slideably adjustable resistive T-network connecting the output of said second amplifier and the input of said fourth amplifier, the output of said fourth amplifier connected to said output terminal; first resistive circuit means connecting said equalizer input terminal, and the output of said first amplifier, to the input of said fourth amplifier; and second resistive circuit means connecting the output of said third amplifier and the input of said first amplifier.
Claim 17
Dependent Claim
35 words
The equalizer as defined in claim 10 wherein at least one of said resistive T-networks further comprises: a first fixed resistive leg; a second slideably adjustable resistive leg; and a third slideably adjustable resistive leg.
Claim 18
Dependent Claim
23 words
The equalizer as defined in claim 11 wherein at least one of said adjustable resistive T-networks exhibits a geometric variation in effective resistance.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-02-06 | 1976-08-07 | 1977-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-06 | 1980-08-07 | 1981-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-06 | 1984-08-07 | 1985-02-06 | $7700.00 | Window Closed / Lapsed |