US3603772A
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US
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Analog-to-digital converter analyzing system
Assignee: National Aeronautics and Space Administration
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Filing: 1969-09-09
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Granted: 1971-09-07
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Expires: 1989-09-09
Abstract
Abstract A system in which a variable and measurable analog signal, such as a voltage, is supplied to an A/D converter, which is being analyzed. Successive digital outputs, such as numbers, of the converter are determined and temporarily stored for comparison purposes. Based on the relative values of the successive numbers, the input voltage to the converter is varied, both in polarity and in magnitude, until a voltage is reached, which when applied to the converter there exists a 50 percent probability that the output number is one of two adjacent numbers. The voltage magnitude, or simply the voltage, is recorded to represent one indecision zone. Thereafter, the input voltage is varied to determine another indecision zone between a selected output number and another number, different therefrom by one.
Inventors
- 👤 Willis W Allen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 10:08
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/10; H03M1/1071
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
224 words
A system for automatically analyzing an analog-to-digital converter to determine at least one magnitude of an analog input signal which when applied to said converter an equal probability exists that the digital output of said converter is either a first number or a second number, the system comprising: analog integrating means for supplying an analog input signal to said converter; means for sampling the digital output of said converter to provide output numbers at a fixed rate; means coupled to the output of said means for sampling for storing each number and for comparing it with a number previously supplied therefrom; means for applying an analog signal to said analog integrating means to apply a changing analog input signal to said converter so that said first and second numbers are successively provided thereby; and control means coupled to said means for storing and to the input of said means for applying an analog signal to said analog integrating means for utilizing the numbers stored in said means for storing to successively control the polarity and amplitude of an analog signal applied thereby to said analog integrating means, until said analog integrating means supplies said converter with an analog input signal having a magnitude whereby an equal probability exists that the output number of said converter is either said first number or said second number.
Claim 2
Independent Claim
224 words
A system for automatically analyzing an analog-to-digital converter to determine at least one magnitude of an analog input signal which when applied to said converter an equal probability exists that the digital output of said converter is either a first number or a second number, the system comprising: analog integrating means for supplying an analog input signal to said converter; means for sampling the digital output of said converter to provide output numbers at a fixed rate; means coupled to the output of said means for sampling for storing each number and for comparing it with a number previously supplied therefrom; means for applying an analog signal to said analog integrating means to apply a changing analog input signal to said converter so that said first and second numbers are successively provided thereby; and control means coupled to said means for storing and to the input of said means for applying an analog signal to said analog integrating means for utilizing the numbers stored in said means for storing to successively control the polarity and amplitude of an analog signal applied thereby to said analog integrating means, until said analog integrating means supplies said converter with an analog input signal having a magnitude whereby an equal probability exists that the output number of said converter is either said first number or said second number.
Claim 3
Independent Claim
154 words
A system for determining an indecision zone of an analog-to-digital converter, the indecision zone bEing defined as an analog input having an amplitude which when applied to said converter the output of said converter is either of two digital numbers producible with equal probability, the system comprising: analog integrating means responsive to an input signal for applying an analog input to said analog-to-digital converter; control means including means for storing the digital output of said converter and for providing control signals as a function of the magnitude relationship between successive digital outputs of said converter; means for sensing said control signals to provide the input signal to said integrating means as a function of said control signals; and recording means coupled to said control means and to said analog integrating means for recording the analog input to said analog-to-digital converter after the occurrence of a preselected number of selected ones of said control signals.
Claim 4
Independent Claim
154 words
A system for determining an indecision zone of an analog-to-digital converter, the indecision zone bEing defined as an analog input having an amplitude which when applied to said converter the output of said converter is either of two digital numbers producible with equal probability, the system comprising: analog integrating means responsive to an input signal for applying an analog input to said analog-to-digital converter; control means including means for storing the digital output of said converter and for providing control signals as a function of the magnitude relationship between successive digital outputs of said converter; means for sensing said control signals to provide the input signal to said integrating means as a function of said control signals; and recording means coupled to said control means and to said analog integrating means for recording the analog input to said analog-to-digital converter after the occurrence of a preselected number of selected ones of said control signals.
Claim 5
Dependent Claim
74 words
The arrangement as recited in claim 2 wherein said control signals include a first and second control signal indicating that a present digital output of said converter is greater by one and smaller by one respectively, from a previous digital output and means for recording include means for counting said first and second control signals to record said analog input after the occurrence of a selected number of said first and second control signals.
Claim 6
Dependent Claim
45 words
The arrangement as recited in claim 3 wherein said means for sensing include bipolar input signal producing means for reversing the magnitude and polarity of said input signal to said integrating means when said control signal is either a first or a second control signal.
Claim 7
Dependent Claim
60 words
The arrangement as recited in claim 4 wherein said control means include means for providing a third control signal when two successive digital outputs of said converter are the same, and said sensing means include means for controlling the amplitude of said input signal to said integrating means as a function of a predetermined number of successive third control signals.
Claim 8
Dependent Claim
165 words
The arrangement as recited in claim 2 wherein the storing means of said control means include a first unit for storing an output digital number of said converter and a second unit storing a previous output digital number of said converter, and said control means include subtracting means for providing a first control signal when the number in said first unit is greater by one than the number in said second unit, a second control signal when the number in said first unit is smaller by one than the number in said second unit and a third control signal when the two numbers are equal, and said sensing means include means for decreasing the amplitude and reversing the polarity of the input signal to said integrating means in response to either a first control signal or a second control signal supplied thereto, said sensing means increase the amplitude of said input signal in response to a preselected number of successive third control signals supplied thereto.
Claim 9
Dependent Claim
140 words
The arrangement as recited in claim 6 wherein said sensing means include a detector for providing a ramp reversal signal and a decrementing signal whenever a first or a second control signal is supplied thereto, said detector providing an increment signal whenever said preselected number of successive third control signals is detected, said sensing means including a bidirectional shift register responsive to said decrement and increment signals for shifting a binary digit of a multibit number therein whereby to double the number in response to an increment signal and reduce the number by a factor of two in response to a decrement signal, and a bipolar digital-to-analog converter, for providing said input signal whose amplitude is a function of the number in said shift register and the polarity as a function of either said first or said second control signals.
Claim 10
Independent Claim
98 words
A system for analyzing an analog-to-digital converter comprising: first means for supplying a variable analog input to an analOg-to-digital converter; second means for storing successive digital outputs of said analog-to-digital converter; third means for providing an output indicative of the difference between the digital outputs, stored in said second means; fourth means, to which the output from said third means is supplied, for controlling said first means to control the analog input which is supplied by said first means to said analog-to-digital converter; and fifth means coupled to at least said first means for measuring said analog input.
Claim 11
Independent Claim
98 words
A system for analyzing an analog-to-digital converter comprising: first means for supplying a variable analog input to an analOg-to-digital converter; second means for storing successive digital outputs of said analog-to-digital converter; third means for providing an output indicative of the difference between the digital outputs, stored in said second means; fourth means, to which the output from said third means is supplied, for controlling said first means to control the analog input which is supplied by said first means to said analog-to-digital converter; and fifth means coupled to at least said first means for measuring said analog input.
Claim 12
Dependent Claim
80 words
The arrangement as recited in claim 8 wherein said analog-to-digital converter is characterized by a time t, where t represents the time interval between successive digital outputs which are read out from said analog-to-digital converter and said first means is operable to provide a maximum change in said analog input which is not greater than 1/2 V per t, where V represents a potential difference which results in a change of one in the digital output of said analog-to-digital converter.
Claim 13
Dependent Claim
40 words
The arrangement as recited in claim 8 wherein the output of said third means is indicative of a change of zero between the digital outputs stored in said second means, or a difference of +1, or a difference of -1.
Claim 14
Dependent Claim
43 words
The arrangement as recited in claim 10 further including means for coupling said third means to said fifth means whereby said fifth means measure said analog input after a preselected number of either +1 or -1 differences are indicated by said third means.
Claim 15
Dependent Claim
80 words
The arrangement as recited in claim 11 wherein said analog-to-digital converter is characterized by a time t, where t represents the time interval between successive digital outputs which are read out from said analog-to-digital converter and said first means is operable to provide a maximum change in said analog input which is not greater than 1/2 V per t, where V represents a potential difference which results in a change of one in the digital output of said analog-to-digital converter.
Claim 16
Dependent Claim
106 words
The arrangement as recited in claim 12 wherein said fourth means includes a bi-directional shift register and detecting means responsive to an output of said third means which indicates either a +1 difference or -1 difference for shifting said shift register in a first direction, and being further responsive to a selected number of outputs of said third means, all of which indicate a zero difference, for shifting said shift register in a second direction, opposite said first direction, said fourth means further including a digital-to-analog converter for providing an analog output having a magnitude which is a function of a count in said shift register.
Claim 17
Dependent Claim
73 words
The arrangement as recited in claim 13 wherein said digital-to-analog converter is a bipolar digital-to-analog converter, and said third means further include means for providing a pulse from said detecting means to said bipolar digital-to-analog converter to reverse the polarity of its analog output, whenever said detecting means sense that the output of said third means indicates either a +1 or a -1 difference between the digital numbers, stored in said second means.
Claim 18
Dependent Claim
49 words
The arrangement as recited in claim 14 wherein a shift in said shift register in said first direction results in a reduction in its content by a factor of 2, and a shift in said second direction results in an increase in its content by a factor of 2.
Claim 19
Independent Claim
133 words
The method of automatically determining an indecision zone of an analog-to-digital converter, the indecision zone representing the amplitude of an analog input which when applied to the analog-to-digital converter, an equal probability exists that the digital output is one of two adjacent numbers, the steps comprising: comparing two successive digital outputs of the analog-to-digital converter, and providing a comparison-indicaTing output which indicates the difference between the compared digital outputs; utilizing the comparison-indicating output to vary the analog input to the analog-to-digital converter so that the comparison-indicating output represents either a difference of +X or a difference of -X between the two compared digital outputs, X being an integer; and measuring the analog input to said analog-to-digital converter after a selected number of comparison-indicating outputs indicate differences of either a +X or a -X.
Claim 20
Independent Claim
133 words
The method of automatically determining an indecision zone of an analog-to-digital converter, the indecision zone representing the amplitude of an analog input which when applied to the analog-to-digital converter, an equal probability exists that the digital output is one of two adjacent numbers, the steps comprising: comparing two successive digital outputs of the analog-to-digital converter, and providing a comparison-indicaTing output which indicates the difference between the compared digital outputs; utilizing the comparison-indicating output to vary the analog input to the analog-to-digital converter so that the comparison-indicating output represents either a difference of +X or a difference of -X between the two compared digital outputs, X being an integer; and measuring the analog input to said analog-to-digital converter after a selected number of comparison-indicating outputs indicate differences of either a +X or a -X.
Claim 21
Dependent Claim
10 words
The method as recited in claim 16 wherein X 1.
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) | 1974-09-06 | 1975-03-08 | 1975-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-06 | 1979-03-08 | 1979-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-06 | 1983-03-08 | 1983-09-07 | $7700.00 | Window Closed / Lapsed |