SU1698861A1 - Alternating voltage calibrator - Google Patents

Abstract

The invention relates to electrical measuring equipment and can be used to verify and calibrate digital voltmeters. The calibrator allows for improved installation accuracy and stability of the calibrator output voltage. To do this, n comparators 10 and (n +1) are input into the calibrator. 1W-NOT 11 and I 12 input logic switches. Comparator 10wind-5 produces a more accurate approximation of the output voltage amplitude to the value of a constant reference voltage. Due to STOMV, the state of the reversible counter 5 does not change every period, which increases the stability of the output voltage. The calibrator also contains a sinusoidal voltage generator 1, a first voltage divider 2, a comparator 3, a driver 4, a reference voltage source 6, a second voltage divider 7, logic elements 2I-HE 8.9. 1 il. 0 co oo 00 &

Description

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The invention relates to electrical measuring equipment and can be used to verify and calibrate digital voltmeters.

The aim of the invention is to improve the accuracy of the installation and the stability of the output voltage.

The drawing shows a diagram of the proposed variable voltage calibrator.

The ac voltage calibrator contains a sinusoidal voltage generator 1 connected in series, a first voltage divider 2 and a comparator 3, as well as a driver 4, a reversible counter 5 and a voltage sensor 6 in series and a second voltage divider 7, in addition, the first 8 and the second 9 logical elements 2I- NOT, n comparators 10, (n + 1) inputs

logical elements OR-NOT 11 and 12. The output of the second voltage divider 7 is connected to the generator input 1 of a 1-shaped voltage and to the information input of the comparator 3, the control input of which is connected to the first inputs of the first 8 and second 9 logic elements 2I-NOT and to the output of the imager 4. The input of the imager 4 is connected to the address output of the generator 1 sinusoidal voltage. The outputs of the first 8 and second 9 logic elements 2I-NOT are connected respectively to the first and second counting inputs of the reversing counter 5. The discharge outputs of the reversing counter 5 are connected to the control inputs

The first voltage divider 2 is the output of which is the output of the calibrator. The first information inputs and comparators -10 are connected to the output of the first voltage divider 2, and their second information inputs to the output of the second voltage divider 7. The outputs (nf1) of the comparators 3 and 10 are connected to the corresponding inputs of the () input logic elements OR NOT 11 and I 12. The control inputs of the comparators 10 are connected to the output of the imager 4. The outputs of the (P-I) input logic elements OR-NOT 11 and 12 are connected respectively with the second inputs of the first 8 and second 9 logical elements 2I-NOT.

The ac voltage calibrator operates in the following manner.

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At the moment of the generation of the amplitude step of its output voltage U by the generator 1, unit levels of the code are established at the discharge outputs of the address counter of the generator 1.

The shaper 4, when this code is set at its inputs, gives a resolution impulse of comparison of voltages U0 and U9b () C by comparators 3 and 10.

Levels 1 at the outputs of comparators 3 and 10 arise as a result of a comparison operation when the voltage U & b) X at the output of the first divider 2 voltage is less than the voltage U0 from the output of the second voltage divider 7.

Logic element 12 at coincidence of unit levels at the outputs of Comparators 3 and 10 is set to state 1, allowing the comparison resolution pulse to pass through logic element 9 to the second counting input of the reversing counter 5 (at the same time O is present at the output of logic element 11). The former 4 generates one comparison resolution pulse for the duration of one voltage period Ur. Thus, the voltage Uewx, when 1 coincides at the outputs of comparators 3 and 10, increases for each subsequent period of voltage Ur one less than 5

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bit until the moment of equality of its amplitude to the set value of the reference voltage U0.

If the comparators 3 and 10 as a result of the comparison receive the levels O, then the logic element 11 fixes the coincidence of the zero levels, while setting to the state 1. At the same time, the comparison resolution pulse goes through the logic element 8 to the first counting input of the reversing counter 5, which leads to a decrease in U6b (x.

When the equality of the output voltage of the calibrator is equal to U0, some of the comparators 3 and 10 will be established by going to the state O, and the rest to 1. Then the outputs of the logic elements 11 and 12 will be set to O, prohibiting the passage of the comparison resolution pulse through the logic elements 8 and 9 to the counting inputs of the reversible counter 5. Thus, on the discharge outputs of the reversing counter 5, the previously established code value is maintained, proportional to the value

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In the proposed calibrator with Ibil close to Zf, the state of the reversible counter 5 does not change every period, thanks to the more accurate work of the group of comparators 3 and 10, in contrast to the prototype.

Due to this, the output voltage of the proposed calibrator is more stable and exactly corresponds to the specified,

Claims (1)

Invention Formula An ac voltage calibrator containing a series-connected sinusoidal voltage generator, a first voltage divider and a comparator, as well as a driver, a reversible counter and a series-connected reference voltage source and a second voltage divider, besides this, the first and second logic elements 2I-HE, the output of the second voltage divider is connected to the input of a sinusoidal voltage generator and to the information input of the comparator, whose control input is connected to the first inputs of the first second and second logic elements 2I-NOT and to the output of the formation bodies, the input of which is connected to the address output of a sinusoidal voltage generator; besides, the outputs of the first and second logic elements 2И-NOT are connected respectively to the first and second inputs of the reversible counter, the discharge outputs of which are connected to the control inputs of the first voltage divider, the output of which is an output of the calibrator, characterized in that, in order to increase the accuracy and stability of the output voltage by eliminating parasitic amplitude modulation, n comparator are additionally introduced c, (pn) -input re logical elements OR-NOT and AND, with the first information inputs of n comparators connected to the output of the first voltage divider, their second information inputs to the output of the second voltage divider, each output (p-1 The -1) -th comparator is connected to the corresponding inputs (p-I) of the input logic elements OR-NOT and I, and the control inputs of the n comparators are connected to the output of the driver, besides the outputs of the (p-I) input logical elements OR-NOT and AND are connected respectively to the second inputs of the first and second logical 2I-NOT elements thereof. five 0 five