Patent US3681699A successfully refreshed from Google Patents.
US3681699A
Expired / Lapsed
US
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Tape channel switching circuit
Assignee: Cogar Corp
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Filing: 1971-02-26
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Granted: 1972-08-01
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Expires: 1991-02-26
Abstract
Abstract A tape channel switching circuit having two operational amplifiers, each of which has its inputs coupled to a respective tape head. The outputs of the two amplifiers are coupled together and extended to the input of a shared amplifier. A control circuit has two output terminals, each connected to one of the input terminals of a respective amplifier. To select one amplifier to the exclusion of the other, the control circuit causes the output of the other operational amplifier to saturate.
Inventors
- 👤 William J Kelly
- 👤 Warren A Reynolds
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:35
CPC Classifications
H; H03; H03K; H03K17/00; H03F; H03F3/00; H03F3/72; H04; H04J; H04J3/00; H04J3/02; H04J3/04; H04J3/047
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
137 words
A switching circuit for extending a selected one of at least two input signals to a common terminal comprising at leaSt first and second operational amplifiers, each of said operational amplifiers having a pair of input terminals and an output terminal, means for coupling each of said at least two input signals to the input terminals of a respective one of said operational amplifiers, control means connected to one of the input terminals of each of said operational amplifiers for selectively applying two different potentials thereto, a first of said potentials allowing the respective operational amplifier to operate in a linear mode and a second of said potentials causing the output of the respective operational amplifier to be saturated, and means for coupling the output terminals of said first and second operational amplifiers to said common terminal.
Claim 2
Dependent Claim
137 words
A switching circuit for extending a selected one of at least two input signals to a common terminal comprising at leaSt first and second operational amplifiers, each of said operational amplifiers having a pair of input terminals and an output terminal, means for coupling each of said at least two input signals to the input terminals of a respective one of said operational amplifiers, control means connected to one of the input terminals of each of said operational amplifiers for selectively applying two different potentials thereto, a first of said potentials allowing the respective operational amplifier to operate in a linear mode and a second of said potentials causing the output of the respective operational amplifier to be saturated, and means for coupling the output terminals of said first and second operational amplifiers to said common terminal.
Claim 3
Dependent Claim
40 words
A switching circuit in accordance with claim 1 further including feedback means connecting the output terminal of each of said operational amplifiers to that one of the respective pair of input terminals to which said control means is not connected.
Claim 4
Dependent Claim
44 words
A switching circuit in accordance with claim 2 wherein said control means applies said different potentials to said operational amplifier input terminals through impedances related to said feedback means such that the pair of input terminals of each of said operational amplifiers are balanced.
Claim 5
Dependent Claim
30 words
A switching circuit in accordance with claim 3 wherein said coupling means includes resistor means connected between the output terminal of each of said operational amplifiers and said common terminal.
Claim 6
Dependent Claim
28 words
A switching circuit in accordance with claim 4 wherein said coupling means further includes capacitor means for eliminating DC components in the signals extended to said common terminal.
Claim 7
Dependent Claim
41 words
A switching circuit in accordance with claim 5 wherein the input terminal of each operational amplifier to which said control means is connected is that one which causes the operational amplifier to exhibit the lowest output impedance when it is saturated.
Claim 8
Dependent Claim
36 words
A switching circuit in accordance with claim 1 wherein the input terminal of each operational amplifier to which said control means is connected is that one which causes the operational amplifier to exhibit the lowest output.
Claim 9
Dependent Claim
30 words
A switching circuit in accordance with claim 1 wherein said coupling means includes resistor means connected between the output terminal of each of said operational amplifiers and said common terminal.
Claim 10
Dependent Claim
28 words
A switching circuit in accordance with claim 8 wherein said coupling means further includes capacitor means for eliminating DC components in the signals extended to said common terminal.
Claim 11
Dependent Claim
41 words
A switching circuit in accordance with claim 8 wherein the input terminal of each operational amplifier to which said control means is connected is that one which causes the operational amplifier to exhibit the lowest output impedance when it is saturated.
Claim 12
Dependent Claim
134 words
A switching circuit for extending a selected one of at least two input signals to a common terminal comprising at least first and second amplifying means, each of said amplifying means having input means and output means, means for coupling each of said at least two input signals to the inputs means of a respective one of said amplifying means, control means connected to the input means of each of said amplifying means for collectively applying two different control signals thereto, a first of said control signals allowing the respective amplifying means to operate in a linear mode and a second of said control signals causing the output of the respective amplifying means to be saturated, and means for coupling the output means of said first and second amplifying means to said common terminal.
Claim 13
Dependent Claim
134 words
A switching circuit for extending a selected one of at least two input signals to a common terminal comprising at least first and second amplifying means, each of said amplifying means having input means and output means, means for coupling each of said at least two input signals to the inputs means of a respective one of said amplifying means, control means connected to the input means of each of said amplifying means for collectively applying two different control signals thereto, a first of said control signals allowing the respective amplifying means to operate in a linear mode and a second of said control signals causing the output of the respective amplifying means to be saturated, and means for coupling the output means of said first and second amplifying means to said common terminal.
Claim 14
Dependent Claim
30 words
A switching circuit in accordance with claim 11 wherein said coupling means includes resistor means connected between the output means of each of said amplifying means and said common terminal.
Claim 15
Dependent Claim
28 words
A switching circuit in accordance with claim 12 wherein said coupling means further includes capacitor means for eliminating DC components in the signal extended to said common terminal.
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) | 1975-08-01 | 1976-01-31 | 1976-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-01 | 1980-01-31 | 1980-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-01 | 1984-01-31 | 1984-08-01 | $7700.00 | Window Closed / Lapsed |