US3725903A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self-calibrating analog to digital converter
Assignee: Bendix Corp
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Filing: 1971-02-09
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Granted: 1973-04-03
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Expires: 1991-02-09
Abstract
Abstract A self-calibrating analog to digital converter wherein, if the full scale reading of the converter is defined as X counts, the calibration formula takes the following form:
Inventors
- 👤 H Kosakowski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 17:18
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/12; H03M1/50
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
182 words
A system including a self-calibrating converter for converting an analog input signal from a signal source to a digital output signal, comprising: means for providing a reference signal; means for providing a signal at ground level; multiplexer means connected to the signal source, to the reference signal means and to the ground level signal means for applying the signals therefrom to the converter; differEnce means connected to the reference signal means and to the multiplexer means for providing a signal corresponding to the difference between the signals therefrom; integrator means connected to the reference signal means for integrating the signal therefrom; comparator means connected to the integrator means and to the difference means for comparing the signals therefrom for providing a signal in accordance with said comparison; counting means connected to the comparator for providing the digital output signal in response to the comparison signal; and calibrating means connected to the counter for providing a calibrated digital output signal having a mid-scale calibration point in accordance with the ground level signal and a lowscale calibration point in accordance with the reference signal.
Claim 2
Independent Claim
182 words
A system including a self-calibrating converter for converting an analog input signal from a signal source to a digital output signal, comprising: means for providing a reference signal; means for providing a signal at ground level; multiplexer means connected to the signal source, to the reference signal means and to the ground level signal means for applying the signals therefrom to the converter; differEnce means connected to the reference signal means and to the multiplexer means for providing a signal corresponding to the difference between the signals therefrom; integrator means connected to the reference signal means for integrating the signal therefrom; comparator means connected to the integrator means and to the difference means for comparing the signals therefrom for providing a signal in accordance with said comparison; counting means connected to the comparator for providing the digital output signal in response to the comparison signal; and calibrating means connected to the counter for providing a calibrated digital output signal having a mid-scale calibration point in accordance with the ground level signal and a lowscale calibration point in accordance with the reference signal.
Claim 3
Dependent Claim
60 words
A system as described by claim 1, wherein the multiplexer means includes: first switching means connected to the signal source, second switching means connected to the ground level signal means and third switching means connected to the reference signal means; and amplifier means connected to the first, second and third switching means for isolating said switching means from the converter.
Claim 4
Dependent Claim
114 words
A system as described by claim 2, wherein the switching means includes: a voltage source for providing a driving voltage; a first current flow control device having an input element connected to the reference signal means, a control element connected to the voltage source and an output element connected to the amplifier means; a second current flow control device having a grounded input element, a control element connected to the voltage source and an output element connected to the amplifier means; and a third current flow control device having an input element connected to the signal source, a control element connected to the voltage source and an output element connected to the amplifier means.
Claim 5
Dependent Claim
58 words
A system as described by claim 3, wherein: the amplifier means has an inverting input element, a non-inverting input element and an output element; the inverting input element is connected to the output element; and the output elements of the first, second and third current flow control devices are connected to the non-inverting input element of the amplifier.
Claim 6
Dependent Claim
55 words
A system as described by claim 1, wherein the difference means includes: an amplifier having an inverting input element connected to the reference signal means, a grounded non-inverting input element connected to the multiplexer and an output element; and a resistor connected to the output element and to the inverting input element of the amplifier.
Claim 7
Dependent Claim
62 words
A system as described by claim 1, wherein the integrator means includes: an amplifier having an inverting input element connected to the reference signal means, a grounded non-inverting input element and an output element connected to the comparator means; a capacitor connected to the inverting input element and to the output element of the amplifier; and a switch connected across the capacitor.
Claim 8
Dependent Claim
51 words
A system as described by claim 1, wherein the comparator means includes: an amplifier having an inverting input element connected to the integrating means, a non-inverting input element connected to the difference means and an output element; and a capacitor connected to the inverting and non-inverting input elements of the amplifier.
Claim 9
Dependent Claim
78 words
A system as described by claim 1, wherein the counting means includes: means for providing a timing pulse; gating means having a first input element connected to the comparator means, a second input element connected to the timing pulse means and an output element at which a signal is provided when the comparison signal and the timing pulse are present; and an N-bit counter connected to the gating means so as to be enabled by the signal therefrom.
Claim 10
Dependent Claim
122 words
A system as described by claim 6, including timing means, compRising: means for providing a starting signal; means for providing a timing pulse; an oscillator connected to the starting signal means and reset by the signal therefrom for providing an output at one logic level; counting means connected to the oscillator and to the timing pulse means and responsive to the timing pulse and the oscillator output at the one logic level for affecting the oscillator to provide an output at a complementary logic level; the integrator switch connected to the oscillator and affected by the oscillator output at the one and complementary logic levels for alternately charging and discharging the capacitor to affect the integrator amplifier for providing a ramp output.
Claim 11
Dependent Claim
33 words
A system as described by claim 9, wherein: the oscillator is connected to the counting means so that said counting means is reset in response to the output at the one logic level.
Claim 12
Dependent Claim
165 words
A system as described by claim 1, wherein the counting means provides a digital signal (Cs), and the calibrating means comprises: first means for providing a digital signal (Cl) corresponding to a low scale calibration point; second means for providing a digital signal (X/2) corresponding to one-half of the full scale reading of the converter; third means for providing a digital signal (Cl - Cm) corresponding to the difference between the low scale calibration point (Cl) and a mid-scale calibration point (Cm); means connected to counting means and to the first means for summing the digital signals therefrom; means connected to the summing means and to the second means for multiplying the signals therefrom; means connected to the multiplying means and to the third means for dividing the signals therefrom; means connected to the dividing means and to the second means for summing the signals therefrom; and said last mentioned summing means providing a calibrated output Co, wherein Co ( Cs- Cl)( X/2 (Cm- Cl))-(X/2).
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) | 1976-04-02 | 1976-10-02 | 1977-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-02 | 1980-10-02 | 1981-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-02 | 1984-10-02 | 1985-04-03 | $7700.00 | Window Closed / Lapsed |