Patent US3763322A successfully refreshed from Google Patents.
US3763322A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital-to-tone converter utilizing a relaxation oscillator
Assignee: Integrated Systems Technology Inc
•
Filing: 1971-10-01
•
Granted: 1973-10-02
•
Expires: 1991-10-01
Abstract
Abstract A relaxation oscillator is formed by a Schmitt trigger circuit and an operational integrator circuit interconnected to form an oscillatory feedback loop. A diode switching network is constructed to receive a plural-bit digital input signal and to modify a circuit parameter in the oscillator feedback loop to adjust the frequency of oscillation in accordance with the coding of the digital input signal. An active low-pass filter circuit is connected to the output of the operational integrator circuit and supplies a sinusoidal tone signal to an output circuit. A switching circuit is responsive to the digital input signal for disabling the output circuit except during the occurrence of predetermined digital code values.
Inventors
- 👤 H Garcia
- 👤 B Peek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 16:02
CPC Classifications
H; H03; H03K; H03K3/00; H03K3/02; H03K3/023; H03K3/0231; H04; H04Q; H04Q1/00; H04Q1/18; H04Q1/30; H04Q1/50
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
140 words
A digital-to-tone converter comprising: relaxation oscillator circuit means including lEvel sensitive bistable circuit means, integrator circuit means and circuit means interconnecting the bistable and integrator circuit means, said bistable means and said interconnecting means forming an oscillatory feedback loop for said integration circuit means; control circuit means coupled in the feedback loop between the bistable circuit means and the integrator circuit means and responsive to a digital input signal for controlling a circuit parameter in the feedback loop for adjusting the frequency of oscillation in accordance with the coding of the digital input signal, an output terminal; output circuit means coupled to the oscillator circuit means for supplying an oscillatory signal to said output terminal; and switching circuit means responsive to the digital input signal for disabling the output circuit means except during the occurrence of predetermined digital code values.
Claim 2
Dependent Claim
140 words
A digital-to-tone converter comprising: relaxation oscillator circuit means including lEvel sensitive bistable circuit means, integrator circuit means and circuit means interconnecting the bistable and integrator circuit means, said bistable means and said interconnecting means forming an oscillatory feedback loop for said integration circuit means; control circuit means coupled in the feedback loop between the bistable circuit means and the integrator circuit means and responsive to a digital input signal for controlling a circuit parameter in the feedback loop for adjusting the frequency of oscillation in accordance with the coding of the digital input signal, an output terminal; output circuit means coupled to the oscillator circuit means for supplying an oscillatory signal to said output terminal; and switching circuit means responsive to the digital input signal for disabling the output circuit means except during the occurrence of predetermined digital code values.
Claim 3
Dependent Claim
87 words
A digital-to-tone converter comprising: Schmitt trigger circuit means; integrator circuit means; adjustable impedance means coupling the output of the Schmitt trigger circuit means to the input of the integrator circuit means; feedback circuit means coupling the output of the integrator circuit means back to the input of the Schmitt trigger circuit means; and control circuit means coupled to the adjustable impedance means and responsive to a digital input signal for controlling the impedance of the adjustable impedance means in accordance with the coding of the digital signal.
Claim 4
Dependent Claim
87 words
A digital-to-tone converter comprising: Schmitt trigger circuit means; integrator circuit means; adjustable impedance means coupling the output of the Schmitt trigger circuit means to the input of the integrator circuit means; feedback circuit means coupling the output of the integrator circuit means back to the input of the Schmitt trigger circuit means; and control circuit means coupled to the adjustable impedance means and responsive to a digital input signal for controlling the impedance of the adjustable impedance means in accordance with the coding of the digital signal.
Claim 5
Dependent Claim
117 words
A digital-to-tone converter comprising: a Schmitt trigger circuit; an operational integrator circuit; a resistor network coupling the output of the Schmitt trigger circuit to the input of the operational integrator circuit; feedback circuit means coupling the output of the operational integrator circuit back to the input of the Schmitt trigger circuit; a plurality of switching devices connected to the resistor network for modifying the attenuation factor between the output of the Schmitt trigger circuit and the input of the operational integrator circuit; and a decoder network coupled to the resistor network switching devices and responsive to a digital input signal for controlling the resistor network attenuation factor in accordance with the coding of the digital input signal.
Claim 6
Dependent Claim
117 words
A digital-to-tone converter comprising: a Schmitt trigger circuit; an operational integrator circuit; a resistor network coupling the output of the Schmitt trigger circuit to the input of the operational integrator circuit; feedback circuit means coupling the output of the operational integrator circuit back to the input of the Schmitt trigger circuit; a plurality of switching devices connected to the resistor network for modifying the attenuation factor between the output of the Schmitt trigger circuit and the input of the operational integrator circuit; and a decoder network coupled to the resistor network switching devices and responsive to a digital input signal for controlling the resistor network attenuation factor in accordance with the coding of the digital input signal.
Claim 7
Dependent Claim
93 words
A digital-to-tone converter in accordance with claim 3 wherein the Schmitt trigger circuit includes: a non-inverting amplifier having input and output terminals; a pair of feedback resistors connected in series between the output and input terminals of the amplifier; a pair of Zener diodes connected in series in an opposite polarity manner between a point intermediate the feedback resistors and circuit ground; and an input resistor connecting the feedback circuit means to the input of the amplifier; the input side of the resistor network being connected to a point intermediate the feedback resistors.
Claim 8
Dependent Claim
61 words
A digital-to-tone converter in accordance with claim 3 wherein the operational integrator circuit includes: an inverting amplifier having input and output terminals; a feedback capacitor connected between the amplifier output and input terminals; and an input resistor connecting the output side of the resistor network to the amplifier input terminal; the feedback circuit means being connected to the amplifier output terminal.
Claim 9
Dependent Claim
121 words
A digital-to-tone converter in accordance with claim 3 wherein: the resistor network includes a plurality of series-connected resistors connected in series between the output of the Schmitt trigger circuit and circuit ground, the input of the operational integrator circuit being connected to a point intermediate two of these series-connected resistors, and the resistor network further includes a plurality of additional resistors each having one terminal thereof connected to a point intermediate two of the series-connected resistors; and the plurality oF switching devices includes a plurality of transistors each connected in series by its emitter and collector electrodes between the other terminal of a different one of the additional resistors and circuit ground, the base electrodes being connected to the decoder network.
Claim 10
Dependent Claim
50 words
A digital-to-tone converter in accordance with claim 3 wherein the decoder network is a diode switching network having a plurality of input terminals for receiving a plural-bit parallel-type digital input signal and a plurality of output terminals individually connected to different ones of the plurality of resistor network switching devices.
Claim 11
Dependent Claim
51 words
A digital-to-tone converter in accordance with claim 3 and including: an output terminal; filter circuit means responsive to the signal appearing at the output of the operational integrator circuit for producing a sinusoidal signal of the same frequency; and output circuit means for supplying the sinusoidal signal to said output terminal.
Claim 12
Dependent Claim
34 words
A digital-to-tone converter in accordance with claim 8 and including switching circuit means responsive to the digital input signal for disabling the output circuit means except during the occurrence of predetermined digital code values.
Claim 13
Dependent Claim
59 words
A digital-to-tone converter in accordance with claim 3 and including: an output terminal; output circuit means coupled to the output of the operational integrator circuit for supplying an alternating signal to said output terminal; and switching circuit means responsive to the digital input signal for disabling the output circuit means except during the occurrence of predetermined digital code values.
Claim 14
Dependent Claim
99 words
A digital-to-tone converter comprising: relaxation oscillator circuit means including a Schmitt trigger circuit, an operational integrator circuit and circuit means interconnecting the Schmitt trigger circuit and the operational integrator circuit, said Schmitt trigger circuit and said interconnecting means forming an oscillatory feedback loop for said integrator circuit means; and control in the feedback loop circuit means coupled between the Schmitt trigger circuit and the integrator circuit means and responsive to a digital input signal for controlling a circuit parameter in the feedback loop for adjusting the frequency of oscillation in accordance with the coding of the digital input signal.
Claim 15
Dependent Claim
99 words
A digital-to-tone converter comprising: relaxation oscillator circuit means including a Schmitt trigger circuit, an operational integrator circuit and circuit means interconnecting the Schmitt trigger circuit and the operational integrator circuit, said Schmitt trigger circuit and said interconnecting means forming an oscillatory feedback loop for said integrator circuit means; and control in the feedback loop circuit means coupled between the Schmitt trigger circuit and the integrator circuit means and responsive to a digital input signal for controlling a circuit parameter in the feedback loop for adjusting the frequency of oscillation in accordance with the coding of the digital input signal.
Claim 16
Dependent Claim
107 words
A digital-to-tone converter comprising: relaxation oscillator circuit means including level sensitive bistable circuit means, integrator circuit means and circuit means interconnecting the bistable and integrator circuit means, said bistable circuit means and said interconnecting means forming an oscillatory feedback loop for said integrator circuit means; and circuit means coupled in the feedback loop between the bistable circuit means and the integrator circuit means and including a switching means and a means responsive to a digital input signal for controlling the switching means to modify a circuit parameter in the feedback loop for adjusting the frequency of oscillation in accordance with the coding of the digital input signal.
Claim 17
Dependent Claim
107 words
A digital-to-tone converter comprising: relaxation oscillator circuit means including level sensitive bistable circuit means, integrator circuit means and circuit means interconnecting the bistable and integrator circuit means, said bistable circuit means and said interconnecting means forming an oscillatory feedback loop for said integrator circuit means; and circuit means coupled in the feedback loop between the bistable circuit means and the integrator circuit means and including a switching means and a means responsive to a digital input signal for controlling the switching means to modify a circuit parameter in the feedback loop for adjusting the frequency of oscillation in accordance with the coding of the digital input signal.
References Cited (Backward Citations)
US3336444A
Cited
US3510592A
Cited
US3573664A
Cited
US3605021A
Cited
US3651267A
Cited
US3627949A
Cited
US3656066A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-01 | 1977-04-02 | 1977-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-01 | 1981-04-02 | 1981-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-01 | 1985-04-02 | 1985-10-02 | $7700.00 | Window Closed / Lapsed |