SU1429319A1 - Multichannel a-d converter - Google Patents

Abstract

The invention relates to the field of information converters with remote transmission of readings. The known devices do not allow the transmission of information over a single-wire line with high noise immunity at a time. The purpose of the invention is to simplify the device and improve the noise immunity of information transmission. The essence of the proposed solution lies in the fact that the results of one-time measurements, presented in the form of time intervals, are transformed in the measurement channel by means of a digital-in-voltage converter into a weighted sum of signals, which is transmitted over a single-wire communication line and decoded by a parallel analog-digital converter. Then gating and digitizing of all measured values is performed. 1 ce f-ly, G / 1 2 il ..

Description

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The invention relates to information converters and can be used for analog-to-digital conversion of process parameters into digital codes and their remote transmission.

The purpose of the invention is to simplify the device, increase the noise immunity of information transmission,

In FIG, 1, the structure of a multichannel analog-to-digital converter (ADC); on . Fig „2 is a time diagram of the operation of a five-channel converter,

The converter contains a generator of 1 pulses, converters 2 of a measured value in a time interval, two sources 3 of the reference voltage, a digital-to-analog converter (D / A) A, a link 5 of the ADC 6, a driver 7 of pulses, a clock generator 8, counters 9, a register 10, the indicator 11. When using the fiber optic waveguide 12, the device further comprises light-emitting and photosensitive elements 13 and 14, respectively.

The converter works as follows

A pulse from the output of the generator 1 triggers the channel converters 2, and the signal at the outputs of the converters is set to one and the output signal of the DAC 4 reaches the maximum level (FIG. 2a) o

On the receiving side, the driver 7 generates a control pulse (FIG. 2c) along the front edge of the input signal, the front of which is driven. There is a copying of the measurement result from the counters 9 into the register 10, and the potential resets the counters 9. The transmitted signal with the frequency of the clock generator 8, ADC 6, is converted into a digital code. As the measurement of the converters 2 finishes, the output signal of the DAC 4 decreases stepwise to the minimum value (Fig. 2a). At the outputs of the ADC 6, pulses are produced (Fig. 26). The duration of which corresponds to the output signals of the 2 converters, Data The signals arrive at the counting counter count input 9, which is used to calculate the pulse duration. The result of counting is indicated by indicator 11,

The number of channels used to measure K depends on the size of the applied DAC and A / D converters and the level of interference, and when transmitting through a fiber optic waveguide it depends on the accuracy of converting voltage to the counting intensity and again to voltage.

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where E is the sign of the integer function

rounding toward the nearest integer; reference stress value

served on the DAC and ABD; noise level or error

transfer.

The proposed converter makes it possible to use a single-wire shielded communication line for transmitting information via K channels.

Claims (2)

Invention Formula 1, A multichannel analog-to-digital converter containing a pulse shaper 9 pulse generator and in each channel a measured value converter into a time interval, the control of which input is connected to the output of the pulse generator, a communication line, in each channel a serially connected counter, register and the indicator, and the reset inputs of the counters and the clock inputs of the channel registers are combined, characterized in that, for the purpose of simplification, a clock generator, reference voltage sources, analog-digital digital and digital analogue converters, the digital inputs of the latter of which are connected to the outputs of the corresponding converters of the measured value in the time interval, the analog input is connected to the output of the first voltage source, the output is connected to the information input of the analog-digital converter, the analog input which is connected to the output of the second source of the reference voltage, the distant outputs are connected to the counter enable inputs of the counters of the corresponding trunk: channels, counting inputs of which connected to the clock input of the analog-to-digital converter and connected to the output of the clock generator, the input of the pulse shaper is connected to the output of the communication line, and the output - to the reset input of the channel counter. 2. The converter according to claim 1, characterized in that, s at 1429319 The purpose of increasing the noise immunity of information transmission is the communication line made on the light-connected element, fiber-optic light guide and photosensitive element, with the light-emitting input and the photosensitive element output being respectively the input and output of the communication lines. U 13: g- - B p l IG