US3739196A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Function generator
Assignee: Tavis Corp
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Filing: 1971-09-23
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Granted: 1973-06-12
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Expires: 1991-09-23
Abstract
Abstract A function generator comprises an openable and closeable seriescircuit path having a node and which is closed only while a voltage at the node has a predetermined polarity with respect to a threshold voltage. An emitter-follower circuit has a transistor biased by a substantially constant voltage source and a resistor divider network. A transistor operated as a diode so as to have at most unity current-gain cooperates with the emitter follower to determine the transition between opening and closing the series-circuit path. The base-emitter junctions of the diodeoperated transistor and the emitter-follower transistor have opposed voltage differences which are substantially equal despite temperature variations so that a highly precise transition is achieved. The closing of the series-circuit path causes current to flow therethrough and such current does not substantially affect the biasing of the emitter-follower because of its current gain characteristic. In a preferred embodiment, each of a plurality of shunting resistors is connectable in parallel with each other and in series with a voltage dropping resistor driven by an operational amplifier. Each shunting resistor is operatively connected at a different threshold so that the function generator has a nonlinear voltage transmission characteristic made up of a plurality of linear segments.
Inventors
- 👤 J Tavis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 01:35
CPC Classifications
G; G06; G06G; G06G7/00; G06G7/12; G06G7/26; G06G7/28
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
247 words
An analog function generator controlled by a first voltage signal, the function generator comprising: circuit means for providing a plurality of threshold voltages; a first impedance having a first terminal for receiving the first voltage signal and having a second terminal forming a common node on which a second voltage is developed when the first voltage signal is received, the second voltage differing from the first voltage when current flows through the first impedance; a plurality of impedances being connectable in parallel circuit relationship with each other, each of the plurality of impedances being associated with a respective one of the threshold voltages; and a plurality of connecting means each for operatively connecting a respective one of the plurality of impedances in seriescircuit relationship with the first impedance only while the second voltage has a predetermined polarity with respect to the threshold voltage associated with the respective impedance; each respective connecting means comprising a current-summing path; a transistor connected between the circuit means and the current-summing path in current-gain configuration whereby changes in the current flowing in the current-summing path do not substantially affect the magnitude of the associated threshold voltage; a semiconductor device having a junction connected in seriescircuit relationship with the respective impedance and between the common node and the current-summing path, the semiconductor device having unity-current-gain while the junction is forwardbiased and substantially no current-gain otherwise, the junction being connected so that it is forward-biased only while the second voltage has the predetermined polarity.
Claim 2
Dependent Claim
247 words
An analog function generator controlled by a first voltage signal, the function generator comprising: circuit means for providing a plurality of threshold voltages; a first impedance having a first terminal for receiving the first voltage signal and having a second terminal forming a common node on which a second voltage is developed when the first voltage signal is received, the second voltage differing from the first voltage when current flows through the first impedance; a plurality of impedances being connectable in parallel circuit relationship with each other, each of the plurality of impedances being associated with a respective one of the threshold voltages; and a plurality of connecting means each for operatively connecting a respective one of the plurality of impedances in seriescircuit relationship with the first impedance only while the second voltage has a predetermined polarity with respect to the threshold voltage associated with the respective impedance; each respective connecting means comprising a current-summing path; a transistor connected between the circuit means and the current-summing path in current-gain configuration whereby changes in the current flowing in the current-summing path do not substantially affect the magnitude of the associated threshold voltage; a semiconductor device having a junction connected in seriescircuit relationship with the respective impedance and between the common node and the current-summing path, the semiconductor device having unity-current-gain while the junction is forwardbiased and substantially no current-gain otherwise, the junction being connected so that it is forward-biased only while the second voltage has the predetermined polarity.
Claim 3
Dependent Claim
34 words
The function generator as defined in claim 1 wherein each semiconductor device in the respective connecting means is a transistor having a base-emitter junction connected between the common node and the respective current-summing path.
Claim 4
Dependent Claim
40 words
The function generator as defined in claim 1 wherein each semiconductor device in the respective connecting means is a transistor having emitter, base, and collector electrodes, the base and collector electrodes being connected together to operate at a common potential.
Claim 5
Dependent Claim
36 words
The function generator as defined in claim 1 wherein the circuit means for providing each threshold voltage comprises a substantially constant voltage source and a resistor divider network having a tap for each different threshold voltage.
Claim 6
Dependent Claim
233 words
Apparatus comprising in combination: a. an operational amplifier having at least one amplifier input terminal and having an amplifier output terminal on which it produces a first voltage, b. a source producing an analog signal, c. means for coupling the source to an amplifier input terminal, d. circuit means for providing a threshold voltage, e. a first impedance having a first terminal receiving the first voltage and having a second terminal forming a common node on which a second voltage is developed, the common node being coupled to an amplifier input terminal to form a negative feedback loop, f. a second impedance, and g. connecting means for operatively connecting the second impedance in series-circuit relationship with the first impedance only while the second voltage has a predetermined polarity with respect to the threshold voltage, the connecting means comprising a current summing path, a transistor connected between the circuit means and the current-summing path in current-gain configuration whereby changes in the current flowing in the current summing path do nOt substantially affect the threshold voltage, and a semiconductor device having a junction connected in series-circuit relationship with the second impedance and between the common node and the current summing path, the semiconductor device having unity-current-gain while the junction is forward-biased and substantially no current gain otherwise, the junction being connected so that it is forward-biased only while the second voltage has the predetermined polarity.
Claim 7
Dependent Claim
233 words
Apparatus comprising in combination: a. an operational amplifier having at least one amplifier input terminal and having an amplifier output terminal on which it produces a first voltage, b. a source producing an analog signal, c. means for coupling the source to an amplifier input terminal, d. circuit means for providing a threshold voltage, e. a first impedance having a first terminal receiving the first voltage and having a second terminal forming a common node on which a second voltage is developed, the common node being coupled to an amplifier input terminal to form a negative feedback loop, f. a second impedance, and g. connecting means for operatively connecting the second impedance in series-circuit relationship with the first impedance only while the second voltage has a predetermined polarity with respect to the threshold voltage, the connecting means comprising a current summing path, a transistor connected between the circuit means and the current-summing path in current-gain configuration whereby changes in the current flowing in the current summing path do nOt substantially affect the threshold voltage, and a semiconductor device having a junction connected in series-circuit relationship with the second impedance and between the common node and the current summing path, the semiconductor device having unity-current-gain while the junction is forward-biased and substantially no current gain otherwise, the junction being connected so that it is forward-biased only while the second voltage has the predetermined polarity.
Claim 8
Dependent Claim
60 words
Apparatus in accordance with claim 5 further comprising circuit means for providing at least one additional threshold voltage; a respective impedance associated with each additional threshold voltage; and a respective connecting means for operatively connecting the associated impedance in series-circuit relationship with the first impedance only while the second voltage has a predetermined polarity with respect to the associated voltage.
Claim 9
Dependent Claim
32 words
Apparatus in accordance with claim 6 wherein each semiconductor device in the respective connecting means is a transistor having a base-emitter junction connected between the common node and the respective current-summing path.
Claim 10
Dependent Claim
38 words
Apparatus in accordance with claim 6 wherein each semiconductor device in the respective connecting means is a transistor having emitter, base, and collector electrodes, the base and collector electrodes being connected together to operate at a common potential.
Claim 11
Dependent Claim
45 words
Apparatus in accordance with claim 6 wherein the source comprises a transducing-indicating device which produces the analog signal, the analog signal having a magnitude which is a non-linear indication signal, and wherein the impedances are resistances having predetermined values for linearizing the amplifier output signal.
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) | 1976-06-11 | 1976-12-11 | 1977-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-11 | 1980-12-11 | 1981-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-11 | 1984-12-11 | 1985-06-12 | $7700.00 | Window Closed / Lapsed |