US3772683A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Analogue to digital converters
Assignee: Gemalto Terminals Ltd
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Filing: 1972-09-27
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Granted: 1973-11-13
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Expires: 1992-09-27
Abstract
Abstract In an auto-ranging analogue-to-digital converter of the integrating type, the integrator has a single preferred decade range of operation, and there is provided means for converting the output of the integrator to an intermediate digital signal having (N+R-1) decades of resolution for analogue signals in the highest range applied to the integrator, where N is the desired number of significant figures of resolution in the output digital signal and R is the number of decade ranges of magnitude of the analogue signal at the input of the integrator. Selection means comprising a shift register is provided for selecting from the intermediate digital signal the N most significant figures thereof to constitute the output digital signal, and there is also provided means for indicating the actual number of significant figures in the intermediate digital, so as to indicate the range in which the magnitude of the analogue signal lies. The lastmentioned means is used, if necessary, to set the integrator to its preferred range of operation for the next measurement cycle with the same analogue signal, and may also be used if necessary to operate an input attenuator at the input of the integrator.
Inventors
- 👤 H Dorey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 19:43
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/12; H03M1/50; H03M1/52
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
229 words
An auto-ranging analogue-to-digital converter of the integrating type, for converting an analogue signal to a digital signal which is representative of the magnitude of the analogue signal and which has N significant figures of resolution in a respective one of R successive ranges of magnitude of the analogue signal, comprising: integrating means responsive to the analogue signal for producing an output signal whose magnitude is dependent upon the magnitude of the analogue signal; means for converting the output signal from the integrating means to an intermediate digital signal which is representative of the magnitude of the analogue signal and which has up to at least (N+R-1) significant figures of resolution for analogue signals whose magnitude lies in the highest range; selection means for selecting from the intermediate digital signal an output digital signal composed of the N most significant figures of the intermediate digital signal; means for producing a further signal indicative of the actual number of significant figurEs in the intermediate digital signal, whereby said further signal is also indicative of the range in which the magnitude of the analogue signal lies; and adjusting means, responsive to said further signal, for adjusting the operation of the integrating means to bring the magnitude of the output signal produced thereby within a single predetermined range of magnitudes, irrespective of the range in which the magnitude of the analogue signal lies.
Claim 2
Dependent Claim
229 words
An auto-ranging analogue-to-digital converter of the integrating type, for converting an analogue signal to a digital signal which is representative of the magnitude of the analogue signal and which has N significant figures of resolution in a respective one of R successive ranges of magnitude of the analogue signal, comprising: integrating means responsive to the analogue signal for producing an output signal whose magnitude is dependent upon the magnitude of the analogue signal; means for converting the output signal from the integrating means to an intermediate digital signal which is representative of the magnitude of the analogue signal and which has up to at least (N+R-1) significant figures of resolution for analogue signals whose magnitude lies in the highest range; selection means for selecting from the intermediate digital signal an output digital signal composed of the N most significant figures of the intermediate digital signal; means for producing a further signal indicative of the actual number of significant figurEs in the intermediate digital signal, whereby said further signal is also indicative of the range in which the magnitude of the analogue signal lies; and adjusting means, responsive to said further signal, for adjusting the operation of the integrating means to bring the magnitude of the output signal produced thereby within a single predetermined range of magnitudes, irrespective of the range in which the magnitude of the analogue signal lies.
Claim 3
Dependent Claim
118 words
A converter as claimed in claim 1, wherein there is provided means for applying the analogue signal to the integrating means during a sampling interval of predetermined duration, so as to cause the output of the integrating means to ramp away from a datum level to a level which constitutes said output signal, and means for applying a reference signal to the integrating means during a digitising interval, so as to cause the output of the integrating means to ramp towards a second datum level, said means for converting the output signal from the integrating means comprising an electrical pulse counter, and clock pulse generator means arranged to supply clock pulses to the counter throughout the digitising interval.
Claim 4
Dependent Claim
17 words
A converter as claimed in claim 2, wherein the first and second datum levels are the same.
Claim 5
Dependent Claim
98 words
A converter as claimed in claim 2, wherein the integrating means includes an input resistance and a capacitance arranged to be charged through the input resistance, at least one of the resistance and the capacitance being adjustable in value, and the adjusting means is operable to adjust the value of said one of the resistance and the capacitance so as to tend to bring the magnitude of said output signal within said single predetermined range, the value of said one of the resistance and the capacitance remaining unchanged between any given sampling interval and its corresponding digitising interval.
Claim 6
Dependent Claim
23 words
A converter as claimed in claim 4, wherein the value of the capacitance is fixed and the value of the resistance is adjustable.
Claim 7
Dependent Claim
39 words
A converter as claimed in claim 5, wherein the resistance comprises a plurality of resistors, and the adjusting means comprises a switching arrangement operable to connect an appropriate combination of the resistors in the input of the integrating means.
Claim 8
Dependent Claim
20 words
A converter as claimed in claim 6, wherein the input resistors of the integrating means are connected together in parallel.
Claim 9
Dependent Claim
36 words
A converter as claimed in claim 7, wherein the switching arrangement comprises at least one switch device, for example a semi-conductor device such as a field effect transistor, connected in series with one of the resistors.
Claim 10
Dependent Claim
61 words
A converter as claimed in claim 2, wherein the means for converting the output signal from the integrating means further includes scaling means arranged to scale down the reference signal and the numerical weight with which the clock pulses are counted by a common factor when the output of the integrating means reaches a value close to the second datum level.
Claim 11
Dependent Claim
104 words
A converter as claimed in claim 9, wherein the output of the integrating means is arranged to ramp from said level constituting said output signal through the second datum level to said value close to the second datum level, and the scaling means includes means for reversing the polarity of the reference signal, so as to cause the output of the integrating means to ramp back from said value to the second datum level, and means for subtracting clock pulses from the count in the counter while the output of the integrating means is ramping back from said value to the second datum level.
Claim 12
Dependent Claim
38 words
A converter as claimed in claim 1, wherein the adjusting means further includes an adjustable attenuator coupled to the input of the integrating means and operable to attenuate the analogue signal before its application to the integrating means.
Claim 13
Dependent Claim
33 words
A converter as claimed in claim 2, wherein the counter has at least (N+R-1) cascaded stages, each of which corresponds to a respective one of the significanT figures of the intermediate digital signal.
Claim 14
Dependent Claim
46 words
A converter as claimed in claim 12, wherein each stage of the counter comprises a plurality m of bistable circuits, and the counter includes switching means operative to switch the configuration of the bistable circuits from that composing the counter to that of a shift register.
Claim 15
Dependent Claim
29 words
A converter as claimed in claim 13, wherein each stage of the counter is a decade stage consisting of a five bit shift register connected in Johnson ring configuration.
Claim 16
Dependent Claim
77 words
A converter as claimed in claim 13, wherein the selection means comprise a further shift register having N stages, each stage corresponding to a respective one of the significant figures of the output digital signal, and means for shifting the figures of intermediate digital signal, in descending order of their significance, from the counter into the further shift register until the N most significant figures of the intermediate digital signal are positioned in the further shift register.
Claim 17
Dependent Claim
108 words
A converter as claimed in claim 15, wherein the further shift register includes switching means operative to transform it into a recirculating shift register when it contains said output digital signal, which switching means operates in response either to the presence of a digital signal representative of a figure of the output digital signal other than zero in the Nth stage of the further shift register when the figures of the output digital signal have been shifted through less than a predetermined number of stages of the further shift register, or to the shifting of the figures of the output digital signal through said predetermined number of stages.
Claim 18
Dependent Claim
59 words
A converter as claimed in claim 15, wherein there is provided means for effecting dynamic readout of the figures of the output digital signal in the further shift register, said means being connected to one stage of the further shift register so as to read out the figures as they are circulated one by one into this one stage.
Claim 19
Dependent Claim
139 words
An electrical pulse counter for use in an analogue-to-digital converter, said counter comprising a plurality P of cascaded stages, each of which counts one number of digit in a number system of radix n and each of which comprises a plurality m of bistable circuits and switching means operative to switch the configuration of the bistable circuits from that composing the counter to that of a shift register, means for supplying shift pulses to the shift register, and means operative between each successive group of m shift pulses to transfer the complement of the number in the Pth stage into the first stage, whereby to transform the number in the 2nd to the Pth stages of the shift register at the start of the group of m pulses into the complement of that number after P groups of pulses.
Claim 20
Dependent Claim
139 words
An electrical pulse counter for use in an analogue-to-digital converter, said counter comprising a plurality P of cascaded stages, each of which counts one number of digit in a number system of radix n and each of which comprises a plurality m of bistable circuits and switching means operative to switch the configuration of the bistable circuits from that composing the counter to that of a shift register, means for supplying shift pulses to the shift register, and means operative between each successive group of m shift pulses to transfer the complement of the number in the Pth stage into the first stage, whereby to transform the number in the 2nd to the Pth stages of the shift register at the start of the group of m pulses into the complement of that number after P groups of pulses.
Claim 21
Dependent Claim
26 words
A counter as claimed in claim 18, wherein the stages of the counter are disposed so that the Pth stage is adjacent to the 1st stage.
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) | 1976-11-12 | 1977-05-14 | 1977-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-12 | 1981-05-14 | 1981-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-12 | 1985-05-14 | 1985-11-13 | $7700.00 | Window Closed / Lapsed |