Low-cost integrable device for the acquisition of electric signals in compliance with the arnic 429 standard
First Claim
1. A device for converting an analog signal of digital data transmission into a digital signal, comprising an analog circuit to which is applied the analog signal, and which is connected to an input of a digital circuit for supplying said digital signal, said analog circuit comprising a capacitor which is charged by said received analog signal via a first resistor, the voltage at the terminals of the capacitor being applied to a terminal connecting said analog circuit to a digital circuit via a second resistor, said digital circuit comprising:
- a measuring and compensating circuit including a digital threshold comparator for comparing the voltage at said capacitor terminals with a threshold voltage, and for transmitting, to a flip-flop, a logic signal whose status is a function of the result of said comparison, a means for periodically applying, via said second resistor, to said capacitor, a charge or discharge compensation voltage depending on the status of said flip-flop, during a first constant period having a predetermined value, so as to charge or discharge said capacitor and bring the voltage of said capacitor back to said threshold voltage, anda filtering and counting circuit comprising a means for counting, by way of an output signal of said flip-flop representative of the flip-flop status, among last N compensations applied to said capacitor, the number of discharge compensations from which is deducted the number of charge compensations, the number thus obtained being at all times representative of said received analog signal.
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Accused Products
Abstract
In order to convert an analog signal of digital data transmission into a digital signal, the device embodying the invention comprises a passive analog circuit comprising a capacitor charged by the analog signal via a first resistor, the voltage at the terminals of the capacitor being applied via a second resistor, at the input of a digital circuit comprising a threshold comparator applying, to a flip-flop, a logic signal which is a function of the result of the comparison with a threshold of the voltage at the input, a means for periodically applying at the input a charge or discharge pulse so as to bring the voltage at the input back to the threshold voltage, a counting circuit for periodically determining a number representative of the analog signal, obtained from subtracting the number of discharges from the number of charges.
34 Citations
13 Claims
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1. A device for converting an analog signal of digital data transmission into a digital signal, comprising an analog circuit to which is applied the analog signal, and which is connected to an input of a digital circuit for supplying said digital signal, said analog circuit comprising a capacitor which is charged by said received analog signal via a first resistor, the voltage at the terminals of the capacitor being applied to a terminal connecting said analog circuit to a digital circuit via a second resistor, said digital circuit comprising:
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a measuring and compensating circuit including a digital threshold comparator for comparing the voltage at said capacitor terminals with a threshold voltage, and for transmitting, to a flip-flop, a logic signal whose status is a function of the result of said comparison, a means for periodically applying, via said second resistor, to said capacitor, a charge or discharge compensation voltage depending on the status of said flip-flop, during a first constant period having a predetermined value, so as to charge or discharge said capacitor and bring the voltage of said capacitor back to said threshold voltage, and a filtering and counting circuit comprising a means for counting, by way of an output signal of said flip-flop representative of the flip-flop status, among last N compensations applied to said capacitor, the number of discharge compensations from which is deducted the number of charge compensations, the number thus obtained being at all times representative of said received analog signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A device for the acquisition of two differential-mode analog signals respectively transmitted by two differential channels, said device comprising:
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an analog circuit comprising two channels in which the two differential-mode signals are respectively applied, each of said channels comprising a capacitor which is charged by the corresponding differential-mode analog signal via a first resistor, the voltage at the terminals of the capacitor being applied to an input of a respective digital circuit via a second resistor, each of said digital circuits supplying at all times a digital value representative of said analog signal applied to the corresponding channel of said analog circuit, by means of;
(i) a measuring and compensating circuit including a digital threshold comparator for comparing the voltage at the capacitor terminals of the corresponding channel with a threshold voltage, and for transmitting to a flip-flop, a logic signal having a status which is a function of the result of said comparison, a means for periodically applying, via said second resistor, to said capacitor, a charge or discharge compensation voltage depending on the status of said flip-flop, during a first constant period having a predetermined value, so as to charge or discharge said capacitor and bring the voltage of said capacitor back to said threshold voltage, and (ii) a filtering and counting circuit comprising a means for counting, by way of an output signal of said flip-flop representative of the flip-flop status, among last N compensations applied to said capacitor, the number of discharge compensations from which is deducted the number of charge compensations, the number thus obtained being at all times representative of said received analog signal,digital comparators for detecting different voltage levels by means of the digital values representative of the input differential-mode analog signals, and a logic circuit designed to generate two logic signals representative of the input analog signals, from the signals coming from said digital comparators. - View Dependent Claims (11, 12, 13)
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Specification