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US3569957A
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Analogue to digital converter with isolated inputs
Assignee: International Business Machines Corp
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Filing: 1968-12-23
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Granted: 1971-03-09
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Expires: 1988-12-23
Abstract
Abstract An analog to digital converter with isolated inputs is provided wherein each of a plurality of input signal channels comprises a transformer and a source of input signals. A second transformer is coupled between the first transformer and the source of input signals and a source of pulses is coupled through the second transformer to actuate a chopper means for producing a modulated signal proportional to the input to the secondary of the transformer. The modulated signal from a selected channel is coupled to an integrating means for a predetermined time as a digital signal generating means is actuated. At the expiration of the predetermined time the polarity of the input signal is detected and a reference voltage input channel is energized to couple to the input of the integrator a reference voltage of the opposite polarity to the input signal while the digital signal generating means is actuated. When the output of the integrator reaches its initial level, the digital signal generating means then holds the digital representation of the input signal.
Inventors
- 👤 Robert J Masterson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:14
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/12; H03M1/50; H03M1/52; H03M1/1205
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
171 words
An analog to digital converter for producing comprising digital representation of the magnitude of an analog signal of unknown magnitude comprising: a plurality of input signal channel means each comrpsing a transformer, an analog signal source and means for producing a modUlated signal proportional to said analog signal through said transformer; means for selecting one of said plurality of input signal channels means; means for integrating the modulated signal from said selected channel for a predetermined time; a reference signal channel means comprising a transformer, a plurality of reference signal sources and means for producing a modulated signal proportional to said reference signal through said transformer; means for selectively coupling a reference signal of polarity opposite to the polarity of said analog signal from said reference signal channel means to said integrating means; means for detecting when the output of said integrating means reaches its initial level; and digital signal generating means responsive to the time of said integration to generate a digital representation of the analog of the input signal.
Claim 2
Dependent Claim
171 words
An analog to digital converter for producing comprising digital representation of the magnitude of an analog signal of unknown magnitude comprising: a plurality of input signal channel means each comrpsing a transformer, an analog signal source and means for producing a modUlated signal proportional to said analog signal through said transformer; means for selecting one of said plurality of input signal channels means; means for integrating the modulated signal from said selected channel for a predetermined time; a reference signal channel means comprising a transformer, a plurality of reference signal sources and means for producing a modulated signal proportional to said reference signal through said transformer; means for selectively coupling a reference signal of polarity opposite to the polarity of said analog signal from said reference signal channel means to said integrating means; means for detecting when the output of said integrating means reaches its initial level; and digital signal generating means responsive to the time of said integration to generate a digital representation of the analog of the input signal.
Claim 3
Dependent Claim
50 words
The analog to digital converter according to claim 1 wherein said means for producing a modulated signal comprises: a source of electrical pulses; a chopping means in said input signal channel means; a second transformer connected to couple said electrical pulses to said chopping means to produce said modulated signal.
Claim 4
Dependent Claim
27 words
The analog to digital converter according to claim 2 wherein said chopping means comprises a pair of field effect transistors in series in said input channel means.
Claim 5
Dependent Claim
32 words
The analog to digital converter according to claim 1 wherein said digital representation generating means comprises; a counter; a source of pulses; and means for selectively gating said pulses to said counter.
Claim 6
Dependent Claim
211 words
An analog to digital converter for producing a digital representation of the magnitude of an analog signal of unknown magnitude comprising: a plurality of inout signal channel means each comprising a transformer, an analog signal source and means for producing a modulated signal proportional to said analog signal through said transformer; means for selecting one of said plurality of input signal channel means; means for integrating the modulated signal from said selected channel for a predetermined time; a reference signal channel means comprising a transformer, a plurality of reference signal sources and means for producing a modulated signal proportional to said reference signal through said transformer; means for selectively coupling a reference signal of polarity opposite to the polarity of said analog signal from said reference signal channel means to said integrating means; means for detecting when the output of said integrating means reaches a predetermined level; means for selectively coupling a second reference signal of polarity opposite to the polarity of said analog signal from said reference signal channel means to said integrating means; means for detecting when the output of said integrating means reaches its initial level; and digital signal generating means responsive to the time of said integration to generate a digital representation of the analog input signal.
Claim 7
Dependent Claim
211 words
An analog to digital converter for producing a digital representation of the magnitude of an analog signal of unknown magnitude comprising: a plurality of inout signal channel means each comprising a transformer, an analog signal source and means for producing a modulated signal proportional to said analog signal through said transformer; means for selecting one of said plurality of input signal channel means; means for integrating the modulated signal from said selected channel for a predetermined time; a reference signal channel means comprising a transformer, a plurality of reference signal sources and means for producing a modulated signal proportional to said reference signal through said transformer; means for selectively coupling a reference signal of polarity opposite to the polarity of said analog signal from said reference signal channel means to said integrating means; means for detecting when the output of said integrating means reaches a predetermined level; means for selectively coupling a second reference signal of polarity opposite to the polarity of said analog signal from said reference signal channel means to said integrating means; means for detecting when the output of said integrating means reaches its initial level; and digital signal generating means responsive to the time of said integration to generate a digital representation of the analog input signal.
Claim 8
Dependent Claim
50 words
The analog to digital converter according to claim 5 wherein said means for producing a modulated signal comprises: a source of electrical pulses; a chopping means in said input signal channel means; a second transformer connected to couple said electrical pulses to said chopping means to produce said mudulated signal.
Claim 9
Dependent Claim
27 words
The analog to digital converter according to claim 6 wherein said chopping means comprises a pair of field effect transistors in series in said input channel means.
Claim 10
Dependent Claim
75 words
The analog to digital converter according to claim 5 wherein said digital representation generating means comprises: a counter including a cirst group of high order positions and a second group of low order position; a source of pulses; and means for gating at least one of said pulses into said first group of positions in said counter and subsequently gating at least another of said pulses into said second group of Positions in said counter.
Claim 11
Dependent Claim
173 words
An analog to digital converter for producing a digital representation of the magnitude of an analog signal of unknown magnitude comprising: a plurality of input signal channels each comprising an input signal source, a chopping means and a first transformer; a source of pulses; a second transformer for selectively coupling said source of pulses to said chopping means in a selected channel to produce at the secondary of the first transformer a modulated signal proportional to the input signal of the selected channel; means for integrating the modulated signal for a predetermined time; means for detecting the sign of the modulated signal; a reference signal channel comprising a plurality of reference signal sources and a third transformer; means for selectively coupling a reference signal of opposite sign to the detected sign through the third transformer to the means of integrating; means for detecting when the output of the integrating means reaches its initial level; and an accumulating means responsive to the time of integration to generate a digital representation of the input signal.
Claim 12
Dependent Claim
173 words
An analog to digital converter for producing a digital representation of the magnitude of an analog signal of unknown magnitude comprising: a plurality of input signal channels each comprising an input signal source, a chopping means and a first transformer; a source of pulses; a second transformer for selectively coupling said source of pulses to said chopping means in a selected channel to produce at the secondary of the first transformer a modulated signal proportional to the input signal of the selected channel; means for integrating the modulated signal for a predetermined time; means for detecting the sign of the modulated signal; a reference signal channel comprising a plurality of reference signal sources and a third transformer; means for selectively coupling a reference signal of opposite sign to the detected sign through the third transformer to the means of integrating; means for detecting when the output of the integrating means reaches its initial level; and an accumulating means responsive to the time of integration to generate a digital representation of the input signal.
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) | 1974-03-08 | 1974-09-07 | 1975-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-08 | 1978-09-07 | 1979-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-08 | 1982-09-07 | 1983-03-09 | $7700.00 | Window Closed / Lapsed |