SU723772A1 - Digital voltmeter of signal effective values - Google Patents

Description

The invention relates to a measurement technique, devices for measuring parameters of signals of the sound and infrasonic ranges. Digital voltmeters are known, which are a combination of an actual value detector with a digital voltmeter. direct current, operating according to the principle of comparing the thermal effects of constant and measured voltages tH. Due to the absence of the possibility of varying the value of the constant time of averaging, the use of these digital voltmeters in the infrasound range is impossible. It is also known a device for measuring actual values, containing an analog-to-digital converter, a pulse generator, the output of which is connected to the input of a pulse frequency divider and adder 2. The device has a low measurement accuracy due to the limited frequency of measurements. The aim of the invention is to improve the measurement accuracy. This is achieved by the fact that a digital-voltmeter of actual values of signals, including an analog-code converter, a pulse generator, the output of which is connected to the input of a pulse frequency separator counter, and the first adder, additionally contains two logic elements and a second adder, and the inputs / first adder are connected to the outputs the first logic element, the inputs of the second adder are connected to the outputs of the second logic element, the first groups of information inputs of the first and second logic elements are connected to you The analog-code converter bit moves, the second groups of information inputs of the first and second logic elements are connected to the high bit outputs of the second adder, the sign bits outputs of the first adder and pulse generator are connected to the first two control inputs of the first and second logic elements, and the output of the pulse-frequency divider counter is connected to the control input of the analog-code converter and the third control inputs of the first and second logic elements; the outputs of the higher bits of the second adder are connected to the second group of information inputs of the first logic element through the additionally introduced switch.

The drawing shows a functional electrical converter circuit.

The input analog signal source x (t) is connected to the analog-code 1 converter, the outputs of which are connected to the first group of information inputs of logic element 2 and the first group of information inputs of logic element 3. The outputs of logic elements 2 and 3 are connected respectively to summatorg1 4 and 5. The second groups of information inputs of the first and second logic elements are connected respectively via switch 6 and directly to the inverse outputs of the higher bits of the adder 5. Output of the sign bit of the totalizer 4 is connected to the first control inputs of logic elements 2 and 3. The clock pulse generator 7 is connected to the counter-frequency divider 8 and the second control inputs of elements 2 and 3. The overflow output of the counter-divider 8 is connected to the control input of the analog-code converter 1 and third control inputs of elements 2 and 3.

The input signal at regular intervals by the overflow signals of the counter 8 is converted in block 1 into a digital code, which remains at the output of this block until the next transformation. During the time between successive transformations, a processing cycle of the next result of conversion is performed, which begins in the overflow cycle of the counter 8 from sending through the element 2 to the adder 4 of the module of the next conversion result. If there is a nonnegative number in the adder 4, when the next clock pulse from the generator 7 appears, the reverse code of the upper bits of the adder 4 is added to the content of the adder 4 through the element 2, and the input signal is transmitted to the input of the adder 5 through the element 3 .

This process continues until a negative number is formed in the next addition in the adder 4, or until the counter 8 is full. When a negative number appears in the adder 4, the transfer of increments into it and the sums of era 5 is blocked by elements 2 and 3. When the counter overflows 8 a command signal is generated next.

analog-to-digital conversion, it sends the modulus of the result of conversion to cf 1mator 4 (with its preliminary cleaning) and adds the return code of the higher bits of the adder 5 to its lsg discharge, which ensures an exponential averaging of the increments arriving at the adder 5 in successive cycles. In this case, in Q 5, the current effective value of the input signal is formed.

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Claims (2)

1. A digital voltmeter of actual values of the signals, including an analog-to-code converter, a pulse generator, the output of which is connected to the input of a pulse frequency divider, and the first adder, characterized in that 0 increase measurement accuracy, he additionally contains two logic elements and, the second adder, moreover, the inputs of the first adder are connected to the outputs of the first logic element, the inputs of the second adder are connected to the outputs of the second logic element, the first groups of information inputs of the first and second logic elements are connected to the outputs of the bits of the analogue converter the code, the second groups of information inputs of the first and second logic elements are connected to the outputs of the old bits of the second adder, the outputs of the sign bit of the first  the adder and pulse generator 1 are connected to the first two control inputs of the first and second logic elements, and the output of the pulse frequency separator counter is connected 0 with the control input of the analog-code converter and the third control inputs of the first and second logic elements. 2. The voltmeter according to claim 1, distinguished by the fact that, in order to increase the accuracy of measurement of signals close in peak factor to sinusoidal, the outputs of the higher bits of the second adder are connected to - the second group of information inputs of the first logic element through the additionally introduced switch. Sources of information taken into account in the examination 55 1, Handbook of radio meters. Edited by Nasonov B.C., Soviet Radio 1976, p.13. 2. Smelkov, V.V., Tsifrovaya ieme60 and equipment of infra-low frequencies. M., Energie, 1975, p. 74 (prototype). zhl  tftiuu 7v / 1 A V f i-iL-i