SU838598A1 - Universal digital integrating voltmeter - Google Patents

Description

The invention relates to digital: electrical measuring equipment and can be used to measure the integral characteristics of a variable signal in a wide frequency range. Known digital voltmeter AC signal containing. voltage converter to time interval, four keys, code-frequency converter, reversible counter, elementary cycle shaper, control unit, arithmetic unit, digital readout 1st unit frequency reference generator, frequency divider, the voltage converter in the time interval connected to the input shaper elementary cycles, and the output with the control inputs of the first and second, keys, the outputs of which are connected to the signal and control inputs of the code-frequency converter, the output of the last connection The third and fourth signal inputs of the opposite inputs of the reversing counter are connected to the outputs of the last keys, and the output is connected to the input of the arithmetic node whose output is connected to the input of the digital reading unit, the outputs of the elementary cycle generator are connected to the clock input of the voltage converter time to the input reset the code-frequency converter and to the input of the control unit, the output of the latter is connected to the control inputs of the formformer of the elementary cycles of the third and fourth quarters keys and the reference oscillator output of the arithmetic unit connected respectively ssignalnym input of the second switch and the input of de-chitel reference frequency, the output of which is connected to the input of the first signalnoktu key. The value of the reference frequency to obtain high measurement accuracy must be selected significantly less than the period T of the input signal. In this case, the measurement error of the voltmeter is mainly determined by the frequency at the output of the code-frequency converter Cll. However, the creation of high-frequency converters of this kind is a difficult technical problem, therefore the measurement result is greatly affected by the discreteness, and this causes the accuracy of the voltmeter to be low.

In addition, the structure described above makes it possible to fully utilize the possibilities of the method incorporated in it in terms of measuring other integral characteristics of the variable signal (mean and average value) in a wide frequency range. which is the disadvantage of a voltmeter. The purpose of the invention is to improve the measurement accuracy and enhance the functionality, which is an additional possibility of measuring the average and average voltage of the variable signal voltages.

The goal is achieved by the fact that a universal digital integrating voltmeter containing a voltage-to-time converter, code-frequency converter, reversible counter, elementary cycle generator, first, second, third and fourth switching blocks, control unit, arithmetic node, digital readout unit , the reference frequency generator, at ET9M the input of the voltage converter in the time interval is connected to the input signal bus, to the input of the elementary cycle generator, the output is the last connected to the clock input of the voltage converter in the time interval and to the input of the control unit, the output of which is connected to the control input of the elementary cycle shaper, and the output of the voltage converter in the time interval is connected to the first inputs of the first and second switching blocks, the second inputs of which are connected to the output of the reference frequency generator, in addition, the first and second inputs of the third switching unit are connected respectively to the output of the code-frequency converter and to the output of the control unit, which It also connects to the first inputs of the arithmetic node and the fourth switching block, introduces a code matching block, a trigger and a counter, the outputs of the first and second switching blocks are connected to opposite inputs of the reversing counter, the output of which is connected to the input of the coincident NID codes and the first input of the arithmetic node , the output of the code matching unit is connected to the first input of the trigger, the output of which is connected to the third input of the third switching unit and the control input of the code-frequency converter, with this output of the third switching unit is connected to the input of the counter, the output of the latter is connected to the second input of the arithmetic node, the output of which is connected to the second input of the fourth switching unit, the output of the latter is connected to the input of the digital reading unit, and

the output of the control unit is connected to the control inputs of the first and second switching blocks, the code matching block, as well as to the second trigger input and the reset inputs of the reversible counter and code-frequency converter, the signal path of which is connected to the output of the reference frequency generator, to the fourth input of the third the switching unit, the second input of the control unit, and the quantization input of the voltage converter in the time interval, the output of which is connected to the third input of the control unit.

FIG. 1 shows a block diagram of a voltmeter; FIG. 2 - time diagrams that show his work.

The voltmeter contains a voltage-to-time converter 1, a code-frequency converter 2, a reversible counter 3, a shaper of 4 elementary cycles, a control unit 5, an arithmetic unit 6, a digital reading unit 7, a reference frequency generator 8, the first and second switching units 9 and 10, block 11 match codes, trigger 12, the third switching unit 13, the counter

14, fourth switching unit

15, with input converter

1 voltage in the time interval is connected to the input of the former 4 elementary cycles, the output of the latter is connected to the clock input of the voltage converter 1 in the time interval and to the input of the control unit 5, the output of which is connected to the control input of the former 4 elementary cycles; The first signal inputs of the first and second switching units 9 and 10 are respectively connected to the output of the voltage converter 1 in the time interval, and the outputs to the opposite inputs of the reversing counter 3, the output of which is connected to the input of the code matching unit 11 and the first y input of the arithmetic node 6, the output of the code matching unit 11 is connected to the first input of the trigger 12, the output of which is connected to the first signal input of the third switching unit 13 and the control input of the code-frequency converter 2, the output of the last connected k tr the third signal input of the third switching unit 13, the output of which is connected to the input of the counter 14, the output of the latter is connected to the second input of the arithmetic node b, the output of which is connected to the input of the fourth switching unit 15, the output of the latter is connected to the input of the digital reading unit 7, the output of the control unit 5 connected respectively to the control inputs of the first, second, third and fourth switching blocks 9, 10, 13 and 15, block 11 of the codes and the arithmetic node 6, as well as with the second input of the trigger 12 and the inputs Reset counter 3 and code-frequency converter 2, the signal input of which is connected with the output of the reference frequency generator 8, with the second signal inputs of the first, second and third switching blocks 9,10 and 13 of the control unit 5 and the input of the converter 1 is wired for a time interval, the output of which is connected to the input of control unit 5. FIG. Figure 2 shows the input signal form 16, pulses 17 arriving at the clock input of the voltage converter 1 in the time interval, code change in the reversible counter 3-18, linear pulses 19 of the variable frequency from the code-frequency converter output. A voltmeter works as follows. In the mode of measuring the effective value of the voltage, the shaper of 4 elementary cycles, based on the signal from the control unit 5, generates the elementary cycles TDD T, i. tT-b (tT--. where I is the current value of the number of the elementary cycle, (i 1,2,3, ..., n) m and n are the coefficients that are selected from the condition of a given measurement accuracy (n) in a given the frequency range (t), arriving at the clock input of the voltage converter 1 in the time interval (Fig. 2u is taken equal to l), so as not to clutter the figure). During the first elementary cycle at the output of the voltage converter 1 in the time interval, the time interval T Til is allocated. where Vx is the integral value of the input signal beyond the tea gauge G. Vg is the reference voltage. Within t U frequency pulses f) from the output of the generator 8 of the reference frequency through the first switching unit 9 are fed to the summing input of the reversible counter 3, the result is the code El TI in the counter equal to, During the second elementary cycle Tdl G for t t2l through the second the switching unit 10 to the subtractive input of the reversible counter 3 will receive the number of N.tar-Twaf pulses. By the end of the second elementary cycle Tdd G21 in the reversible counter 3 there remains the code Ndd Tl, 2 I is equal. N. Sh-N gt gp-ot ot v Vo - At the end of the T-ED 23 after the signal from the control unit 5, the trigger 12 is set to a certain logical state, and its input to the subtraction of the reversible counter 3 continues to send pulses of the frequency fj. If the code in the reversible counter 3 is equal to zero, the block 11 matches, and the trigger 12 returns to the initial state. The information time interval T 1 allocated by trigger 12 is equal to tso-3 1; If N el ll NJ G2, then at the end of 23, the signal from the control unit 5 controls the trigger 12 is set; a certain logical state, and pulses of frequency f are fed to the summing input of the reversible counter 3. The informative time interval T 1 is determined in a similar way. The resulting time interval is fed to the control input of the code-frequency converter 2, having a conversion function of the form M f -i f NO, where f is the pulse frequency at the output of the code-frequency converter 2; - the capacity of the counters of the transducer 2; N is the control counter code of the converter 2. The frequency f during the time T l goes through the third switching unit 13 to the counter 14, the code N 1 in the counter 14 is equal to JNtO T V f- - o o then the elementary cycles are repeated L times. B. As a result, in the counter 4, the NCU code is accumulated. The approved algorithm for reducing the discreteness of the discreteness allows one to conduct two types of quantization (synchronization). The first type of quantization (in terms of frequency f) of filling the intervals of the belt T-e GO is implemented as follows. The end of t i is synchronized with the first pulse f of frequency f that came after the end of the pulse. the result is 13-TCO T Ci O Tti + 43-At + t, tv 3-TCvil- t. + Aty,

where TI VD is the quantized time interval; ds is the time interval between the end of Ted 1 and the first incoming impulse of the frequency —L). hence 2T, d h ss hl1: -l.hts; +: -l1 At. Ы 11 nTcOfit .. Thus, the value of the sum of any number of quantized time intervals mc Til differs from the true one by no more than 1 c. Let us consider the second type of quantization with respect to the frequency f of the filling of the time intervals T D1. When the code N ,,, D, 1 + 1 is written off in a reversible counter with 3 pulses - frequency fj - the end of the informative time interval i T P is determined by the first received frequency pulse f after condition i, (fig. Tj.t ,): As a result, the code written off is equal to,, NC “3 .3-LH,., - AH ,,. from here. S Ni: i Nj nO - "- & N -" - tl Ng CA3-bN + u. rUNj COtbN. where D N j. by equivalent value does not exceed yj. Thus, the introduction of quantization operations allows, with the same requirements for the code-frequency converter 2, to reduce the relative discrete error by a factor of L. After receiving the code N Lj in the counter 14, the elementary cycles are shifted by time t. , as well as presetting the control counter of the code-frequency converter 2 / the same by preparing it for a new cycle of operation, after which the described operations are repeated. As a result, in the counter 14, the code and ViCt I N, u K. v oNo which, as in the known device, receives 8 arithmetic node b, normalization and from

Claims (1)

square root attraction The digital reading unit 7 receives the code Pi about where k is the proportionality coefficient 3, proportional to the actual value of the input signal voltage. In the mode of measuring the average value of the voltage in the first cycle, the shaper of 4 elementary cycles generates the elementary T ,, Cn-mT.t ,, supplied to the clock input of the voltage converter 1 in the time interval by the signal from the control unit 5. At the output of the voltage converter 1, the time intervals for each T are allocated to the time interval (JiJ pulses of frequency f from the output of the reference frequency generator 8 through the first switching unit 9 arrive at the summing input of the reversing counter 3. For n elementary cycles, the code is accumulated in the reversing counter 3 , and Vv, .. where mT.SV code proportional to i: the integral value of the input signal over m, n periods T {ff code proportional to the average value of the input signal. In the second, also to the clock input, the voltage time 1 atomic intervals are applied to the elementary cycles t. - .. T .. At the output of voltage converter 1, time intervals are indicated at the time interval during which pulses fa with a second switching unit 10 are fed to the subtracting input rotor. counter 3. For the n elementary cycles in the reversible counter 3, the code -N -nI | V - SV will remain. This code goes to the arithmetic unit 6, which performs the normalization, as a result, through the fourth switching unit 15 to the digital reading unit 7 enters the code, where K - coefficient ent proportionality proportional srednevypr straightening value voltage input Nogo signgila. In the mode of measuring with the green value, the information voltage, corresponding to a positive half-wave of the input signal, is through the first switching unit. 9 is fed to the summing input of the reversible counter 3, and the information corresponding to the negative half wave through the second switching unit 10 to the subtracting input of the reversing counter 3. As a result, the code,., Is accumulated in the reversing counter 3 n. ii, Vy, - Vu-r, t, 3) 4sv,;, 4i-Vo information for ./Х.ТЭА positive half-wave of the input signal; Ci - information for the negative half-wave of the input signal; elementary cycle This code enters the arithmetic unit 6 that performs normalization. As a result, through the fourth switching unit 15, the digital reading unit 7 enters the code 7 and N -k 1 V V 1 proportional to the average value of the input signal voltage. Thus, the proposed device, besides wider functionality than the known device, has a discrete error of L times smaller, which makes it more accurate. Invention Universal digital integrating voltmeter containing a voltage-to-time converter, code-frequency converter reversible counter , driver, elementary cycles, first, second, third and fourth switching blocks control block, arithmetic, j node digital readout -b The reference frequency generator, while the input of the voltage converter in the time interval is connected to the input signal bus, to the input of the elementary cycle generator, the output of the latter is connected to the clock input of the voltage converter in the time interval and to the input of the control unit, the output of which is connected to the control the input of the generator of elementary cycles, and the output of the voltage converter in the time interval is connected to the first inputs of the first and second switch blocks, the second inputs of which are connected to the output the reference frequency generator, in addition, the first and second inputs of the third switching unit are connected respectively to the output of the code-frequency converter and to the output of the control unit, which is also connected to the first inputs of the arithmetic node and the fourth switching unit, characterized in that and expanding the functionality, a code match block, a trigger and a counter are entered into it, with the outputs of the first and second switching blocks connected to opposite inputs of the reversing account The output of which is connected to the input of the code match unit and the first input of the arithmetic node, the output of the code matching unit is connected to the first trigger input, the output of which is connected to the third input of the third switching unit and the code-frequency control input converter, while the output of the third switching unit is connected with the counter input, the output of the latter is connected to the second input of the arithmetic node, the output of which is connected to the second input of the fourth switching unit, the output of the latter is connected to the input qi the output of the control unit is connected to the control inputs of the first, second switching blocks, the code matching unit, as well as the second trigger input and the reset inputs of the reversible counter and code frequency converter, the signal input of which is connected to the output of the reference frequency generator, the fourth input of the third switching unit, the second input of the control unit and the quantization input of the voltage converter in the time interval, the output of which is connected to the third input of the control unit. Sources, information taken into account in the examination 1. USSR author's certificate in application No. 2600402, 10.31.78. / 7 / L v / t