US3755749A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sound reenforcement equalization system
Assignee: WHITE INSTR Inc
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Filing: 1971-11-22
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Granted: 1973-08-28
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Expires: 1991-11-22
Abstract
Abstract An active filter in combination with a sound reenforcement equalization system is provided. The filter permits variation of the notch frequency over a wide range of frequencies and adjustment of the notch depth from zero to any desired value independent of frequency control. Active filters may be cascaded without additional loss in the pass band.
Inventors
- 👤 Ryswyk C Van
- 👤 C Boner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:06
CPC Classifications
H; H03; H03H; H03H11/00; H03H11/02; H03H11/04; H03H11/12; H03H11/1217
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
132 words
In a sound reenforcement equalization system having a mixer amplifier and a power amplifier, a filter connected between the mixer amplifier and the power amplifier and comprising a filter unit including a pair of integrating amplifiers, means for summing a portion of the output of the filter unit with an input signal from the mixer amplifier to produce a notch response, and means connected with the integrating amplifiers for adjusting the filter for frequency response and notch depth, said filter comprising a filter unit and an adder-subtractor circuit, said filter unit comprising a first integrating amplifier, a second integrating amplifier and feedback means connecting the output of the second integrating amplifier with the input of the first integrating amplifier, said adder-subtractor circuit being connected to the output of the first integrating amplifier.
Claim 2
Dependent Claim
132 words
In a sound reenforcement equalization system having a mixer amplifier and a power amplifier, a filter connected between the mixer amplifier and the power amplifier and comprising a filter unit including a pair of integrating amplifiers, means for summing a portion of the output of the filter unit with an input signal from the mixer amplifier to produce a notch response, and means connected with the integrating amplifiers for adjusting the filter for frequency response and notch depth, said filter comprising a filter unit and an adder-subtractor circuit, said filter unit comprising a first integrating amplifier, a second integrating amplifier and feedback means connecting the output of the second integrating amplifier with the input of the first integrating amplifier, said adder-subtractor circuit being connected to the output of the first integrating amplifier.
Claim 3
Dependent Claim
20 words
A sound reenforcement equalization system as recited in claim 1, including additionally an output amplifier connected to the summing means.
Claim 4
Dependent Claim
31 words
A sound reenforcement equalization system as recited in claim 2, wherein said summing means includes a potentiometer and a resistor connected between one of the integrating amplifiers and said output amplifier.
Claim 5
Dependent Claim
40 words
A sound reenforcement equalization system as recited in claim 1, wherein said frequency response adjusting means comprises a variable resistor connected between the output of one of the integrating amplifiers and the input of the other of said integrating amplifiers.
Claim 6
Dependent Claim
26 words
A sound reenforcement equalization system as recited in claim 1, wherein said notch depth adjusting means includes a potentiometer connected to one of said integrating amplifiers.
Claim 7
Dependent Claim
30 words
A sound reenforcement equalization system as recited in claim 1, wherein said filter comprises a phase splitter and a filter unit, said filter unit comprising a pair of integrating amplifiers.
Claim 8
Dependent Claim
77 words
A sound reenforcement equalization system including, in combination with a mixer amplifier and a power amplifier, an active band-pass filter connected between the mixer amplifier and the power amplifier, said filter including a filter unit comprising a pair of integrating amplifiers and feedback means connecting the output of one of said integrating amplifiers with the input of the other, and a summing output amplifier connected to the filter unit input and to one of said integrating amplifiers.
Claim 9
Dependent Claim
77 words
A sound reenforcement equalization system including, in combination with a mixer amplifier and a power amplifier, an active band-pass filter connected between the mixer amplifier and the power amplifier, said filter including a filter unit comprising a pair of integrating amplifiers and feedback means connecting the output of one of said integrating amplifiers with the input of the other, and a summing output amplifier connected to the filter unit input and to one of said integrating amplifiers.
Claim 10
Dependent Claim
109 words
A sound reenforcement equalization system including, in combination with a mixer amplifier and a power amplifier, a filter connected between the mixer amplifier and the power amplifier, said filter comprising a first integrating amplifier having its input connected to the mixer amplifier, a second integrating amplifier, feedback means connecting the output of the second integrating amplifier with the input of the first integrating amplifier and output means connected to the first integrating amplifier, summing means connected to said filter output means, an output terminal, and an output amplifier having its input connected to the summing means and to the input terminal and its output connected to the output terminal.
Claim 11
Dependent Claim
109 words
A sound reenforcement equalization system including, in combination with a mixer amplifier and a power amplifier, a filter connected between the mixer amplifier and the power amplifier, said filter comprising a first integrating amplifier having its input connected to the mixer amplifier, a second integrating amplifier, feedback means connecting the output of the second integrating amplifier with the input of the first integrating amplifier and output means connected to the first integrating amplifier, summing means connected to said filter output means, an output terminal, and an output amplifier having its input connected to the summing means and to the input terminal and its output connected to the output terminal.
Claim 12
Dependent Claim
32 words
The combination recited in claim 8, wherein the filter output means is adjustable for producing a variable notch response, and wherein the filter feedback means is adjustable for varying the frequency response.
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) | 1976-08-27 | 1977-02-26 | 1977-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-27 | 1981-02-26 | 1981-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-27 | 1985-02-26 | 1985-08-28 | $7700.00 | Window Closed / Lapsed |