SU688987A1 - Converter of the rate of variation of analogue signal into time interval - Google Patents

Description

one

The invention relates to instrumentation engineering, in particular, to converters of the rate of change of an analog signal over a time interval. It can be used in automatic control systems, in particular, in the construction of analog-to-digital converters with dynamic error correction.

A device for measuring the rate of change of an analog signal, consisting of an analog-digital converter of the balancing, increment counter, control triggers and logic elements 1, is known.

The disadvantage of this device lies in its high complexity.

The closest prototype of the invention is a converter comprising a series-connected comparison device, the first input of which is connected to the input of the converter, and the second input is connected to the output of the sawtooth generator, and a device for isolating the difference in time intervals.

Its disadvantage is reduced accuracy, since it’s a constant component of the input signal that takes most of the time to convert it into a time and interval.

The purpose of the invention is to increase the accuracy of the conversion.

The goal is achieved by the fact that a connected converter with a converter, and a device for selecting time intervals, were entered into a sequential switch of small signals, the input of which was connected to the output of the comparator, and an integrator whose output is connected to the second input of the comparison device.

The drawing shows the functional electrical circuit of the converter. The converter contains a comparative device 1, the first input of which is connected to the converter input, a switch 2 of bipolar polarity, the input of which is connected to the output of the comparator device 1, and the output through the integrator 3 is connected to the second input of the comparison device 1, to the output of the last connected device 4 of the selector time interval differences.

The converter works in the following way.

At the moment of time / "start; g-th cycle

The transformer signal at the output of integrator 3 takes a value smaller than the input by the hysteresis value of the comparator device 1. The latter triggers, causing the switch 2 to be thrown, as a result of which the polarity of the signal at the input of integrator 3 is reversed. After that, the integrator output increases at a constant rate. When the value at the moment of the DF is exceeded, its input signal is equal to the hysteresis value of the device 1, the latter switches to the initial state, and then the whole process is repeated.

The operation of the converter can be described by the following equations:

y (4-1) th + J kU, (fJ + a, (1)

p-1

y (n) + a- (tn) -b, (2)

tn

where y (t) is the input signal;

a, b are the hysteresis values of the comparison circuit when the integrator signal changes from below and above, respectively; k is the integrator constant; and o is the switch output signal.

From expressions (1), (2), it follows that g / (Yy (4-1) 1

., (t -tn-l -k (t, -t)

, M, (3)

Where

(4-1) -y (and

(T, -4-l) - ("- 4) The increment sign Ar / in expression (3) is determined by the sign M and is formed by a device for distinguishing the difference in time intervals, which, in the case of the presentation of the final result in digital form, is realized by a reversible counter.

Owing to the distinctive features of the invention, the constant component of the input signal is excluded from the conversion process, as a result of which the conversion rate is increased, which, with changing input signal, provides an increase in accuracy.

Claims (2)

1. USSR author's certificate number 485475, cl. G 06G 3/00, 12.06.73. 2. Temnikov F. E., Slavinsky V. L. Mathematical developmental systems. M., “Energie, 1970, p. 23 (prototype).