US3768009A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Improvements in mark-space analogue to digital converters
Assignee: Gemalto Terminals Ltd
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Filing: 1970-10-16
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Granted: 1973-10-23
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Expires: 1990-10-16
Abstract
Abstract A mark space analogue to digital converter or digital voltmeter has an integrator whose output ramps up and down during one conversion cycle in response to a continuously applied input signal and an intermittently applied opposing reference signal. The reference signal is applied at predetermined intervals and removed each time the integrator output returns to a detection level. The ratio of the time the reference signal is applied to the total time is measured to provide a digital representation of the input signal magnitude. More rapid convergence of the digital output is achieved by programming the said intervals to form a decreasing sequence. Preferably each interval is half the preceding interval.
Inventors
- 👤 H Dorey
- 👤 E Metcalf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:44
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/12; H03M1/50; H03M1/52
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
143 words
An analog to digital converter, comprising integrating and comparing circuit means for responding to first and second electrical signals to provide a net integral output voltage, a bistable device, means for applying the first signal to said circuit means continuously through a conversion interval, means responsive to said bistable device for applying the second signal to said circuit means, means for switching said bistable device to a first state at predetermined times, means for switching said bistable device to a second state when the output voltage reaches a predetermined level, a source of clock pulses, counter means for counting clock pulses during that proportion of the conversion interval when the bistable device is in one of said states, and timing circuit means for varying the intervals between successive ones of the predetermined times in accordance with a predetermined program during the conversion interval.
Claim 2
Dependent Claim
143 words
An analog to digital converter, comprising integrating and comparing circuit means for responding to first and second electrical signals to provide a net integral output voltage, a bistable device, means for applying the first signal to said circuit means continuously through a conversion interval, means responsive to said bistable device for applying the second signal to said circuit means, means for switching said bistable device to a first state at predetermined times, means for switching said bistable device to a second state when the output voltage reaches a predetermined level, a source of clock pulses, counter means for counting clock pulses during that proportion of the conversion interval when the bistable device is in one of said states, and timing circuit means for varying the intervals between successive ones of the predetermined times in accordance with a predetermined program during the conversion interval.
Claim 3
Dependent Claim
140 words
A digital voltmeter, comprising integrating and comparing circuit means responsive to an input and a reference signal to provide a net integral output voltage, a bistable control device, means for applying the input signal to said circuit continuously throughout a conversion interval, means responsive to said bistable control device for applying the reference signal to said circuit means, means for switching said bistable device to a first state at predetermined times, means for switching the bistable device to a second state when the output voltage reaches a predetermined level, a source of clock pulses, a counter arranged to count clock pulses during that proportion of the conversion interval when the bistable device is in one of said states, and timing circuit means for reducing the interval between successive ones of the predetermined times at least once during the conversion interval.
Claim 4
Dependent Claim
140 words
A digital voltmeter, comprising integrating and comparing circuit means responsive to an input and a reference signal to provide a net integral output voltage, a bistable control device, means for applying the input signal to said circuit continuously throughout a conversion interval, means responsive to said bistable control device for applying the reference signal to said circuit means, means for switching said bistable device to a first state at predetermined times, means for switching the bistable device to a second state when the output voltage reaches a predetermined level, a source of clock pulses, a counter arranged to count clock pulses during that proportion of the conversion interval when the bistable device is in one of said states, and timing circuit means for reducing the interval between successive ones of the predetermined times at least once during the conversion interval.
Claim 5
Dependent Claim
30 words
A mark-space analog to digital converter according to claim 1, wherein the timing circuit reduces the length of the intervals at least once during the course of the conversion interval.
Claim 6
Dependent Claim
28 words
A mark-space analog to digital converter according to claim 1, wherein the timing circuit reduces the length of the intervals progressively throughout the course of the conversion interval.
Claim 7
Dependent Claim
22 words
A mark-space analog to digital converter according to claim 4, wherein the timing circuit reduces the intervals progressively by factors of two.
Claim 8
Dependent Claim
51 words
A mark-space analog to digital converter according to claim 5, wherein the timing circuit comprises a source of timing pulses, a binary counter arranged to count these pulses and means responsive to the states of the counter stages successively attaining the same value to switch the bistable to the first state.
Claim 9
Dependent Claim
29 words
A digital voltmeter according to claim 2, wherein the timing circuit reduces the length of the intervals progressively by factors of two throughout the course of the conversion interval.
Claim 10
Dependent Claim
39 words
A voltmeter according to claim 2 and further comprising means for transferring the value accumulated by said counter to a readout staticizer at the end of said conversion interval as a representation of the value of said first signal.
References Cited (Backward Citations)
US3581305A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-22 | 1977-04-23 | 1977-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-22 | 1981-04-23 | 1981-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-22 | 1985-04-23 | 1985-10-23 | $7700.00 | Window Closed / Lapsed |