SU798880A1 - Four-square multiplying device - Google Patents

Description

(54) FOURGQUADRATED POTENTIAL DEVICE

The invention relates to electrical measuring equipment and can be used in multiplying the instantaneous values of two voltages, performing squaring operations, extracting the root, measuring the power and the effective voltage value, incl. in AC circuits. It is known that the quadratic time is a pulsed duplicating device that uses latitude and amplitude modulation of a sequence of pulsed signals proportional to the amplitude of the input voltages, followed by a constant component. The device comprises a triangular voltage generator, a comparison device, a pulse voltage amplifier, an input voltage divider, and an output active filter i. The disadvantage of this device is the narrow frequency band of the multiplied signals (not more than 10 Fu). The closest in technical essence to the present invention is a multiplying device, containing working and compensating bridges on field-effect transistors in a controlled resistance mode, amplifiers and a source: reference voltage. The first multiplied voltage Uy is fed to one of the diagonals of the working bridge, while the transmission coefficient of the working bridge is proportional to the second voltage Uy fed to one of the shoulders of the compensation bridge. The voltage in the second diagonal of the working platform is proportional to K-U, which is amplified by the amplifier. A compensating bridge is connected to the feedback circuit of another amplifier, and a reference stabilized voltage is applied to its diagonal. The transmission coefficient of the compensating bridge is proportional to the voltage Ц With the identity of the working and compensation bridges, and this is achieved by selecting field pairs

The transistors, wallpaper transfer rates of bridges are the same. Consequently, the voltage in the second diagonal of the working bridge is projected {rationally to the product of the SRI

The disadvantage of this four-square multiplying device is the need to select a pair of transistors of the working and compensating bridges, which results in the R non-technological nature of the entire device. In addition, over a wide range of input voltages and temperatures, the non-identity of a pair of field-effect transistors cannot be better, h & l 2%, which reduces the accuracy of the device.

The purpose of the invention is. increase the accuracy of work.

The goal is achieved by the fact that the well-known four-square multiplying device containing a compensating resistive bridge, the first and second arms of which include controllable resistors, and the third and fourth shoulders - permanent resistors, a differential amplifier connected to resistive bridge formed by the first and fourth shoulders of the bridge, and the inverting entrance to the second height of the compensating bridge formed by the second and third shoulders of the bridge the voltage source, the first to the second low-pass filters, the clock pulse generator, the first, second, third, and keys and the first, second, and third inverters are entered, and the information input of the first key is the input of the first factor of the device, the control input of the first the key is connected to the output of the clock pulses; the information input of the second key is connected to the output of the reference voltage source; the control input of the second key is connected to the output of the first inverter, whose input is connected to The output of the generator, clock pulses, outputs and the second keys are combined and connected to the third vertex of the compensating bridge, connected to the third and fourth arms of the bridge; the fourth vertex of the compensating bridge is connected to the zero potential bus; the control input of the third key is connected to the clock pulse generator; the control input of the fourth key is connected to the output of the second inverter, whose input is connected to the output clock pulses for generators, the outputs of the third and fourth keys are connected to inputs of a low-frequency first and second filters, respectively, the first filter output is the output device, the second filter output is connected to one input of the comparison unit, the other input of

0 of which is the input of the second device, the output of the comparison unit is connected to the control input of the first controlled resistor and through the third inverter to the control input

S of the second controlled resistor.

In this way, a temporary separation of the bridge gain control and the multiplication of instantaneous voltage values

In this way, the function of the working and compensating bridges is performed by one bridge, which significantly reduces the components of the errors of the devices.

The drawing is functional

5 diagram of a four-square multiplying device.

The device contains compensating resistive bridge I with controlled resistors 2 and 3 and permanent resistors 4 and 5, differential amplifier 6, keys 7.8, block 9 and 10, generator 11 clock pulses, inverters 12, 13, 14, block 15 comparison (adder), source 16 of reference voltage J, filters 17, 18 low frequencies.

The device works as follows.

One of the multiplied voltages and the reference voltage of the source 16 are alternately connected by switches 7 and 8 to the third vertex of the compensating bridge I.

Claims (1)

The key is controlled by the clock pulses of the generator C. In a half-period, when the clock pulse from the generator C opens the key 8 (key 7 closes), the reference voltage is applied to the compensating bridge I. The unbalance signal of the compensating bridge I is amplified by the differential amplifier 6 and through the open key Yu A low-frequency filter 18 is fed to the input of the comparator unit 15. The second input of the comparison unit 15 supplies the second multiplied voltage Oj (. The input voltage inequality signal is output from the output of the comparison unit 15 directly to the control resistor 2 and through the phase inverter 13 ia controlled resistor 3, changing, thereby, the coefficient the transmission of the compensating bridge is 1-until the comparison unit 15 fixes the equality of the voltages, while the transfer coefficient of the compensating bridge I and the differential amplifier 6 is proportional to the value of the second multiplied voltage –y. The half cycle of the clock pulse opens the key 7 and the key .9 and the keys 8 and Y are closed. The first multiplied voltage C through the key 7 goes to the compensating bridge 1 and is amplified by the differential amplifier 6. Since the key 10 is closed in this half period, then the low-frequency filter 1 constantly has a voltage equal to the voltage applied to the filter 18 at the end of the first field of the clock pulse period. Consequently, the transfer coefficient of the compensating bridge 1 and the differential amplifier 6 in the second half period is equal to n Transmission in the first half period. Taking into account that the transmission coefficient for both half-periods is the same and proportional to the voltage -v i at the output of the differential amplifier 6, the voltage is obtained, which is proportional to the product of the multiplied voltages y and which is fed through {glyuch 9 to the 17 low-pass filter. The accuracy of multiplying the two stresses is determined mainly. The sensitivity of the comparison unit 15 is practically independent of the change in the characteristics of the controlled resistances 2, 3 of the compensating bridge 1. As the controlled resistances 2 and 3, the following can be applied: assemblies of two transistors. Inverters 12 and t4 are designed to change the phase of the control signal (clock pulses) at the input of the keys 8 and 10, respectively, and can be performed on the logical elements NOT. The introduction of a clock pulse generator, switches with switches and inverters allows for temporarily separating the control of the transmission coefficient and the multiplication process itself, as well as eliminating a single bridge, which significantly reduces the error components due to the non-identical fault current characteristics of the controlled resistances. The error rate of the multiplication by the proposed device does not exceed O, O4%. 7 06 This is more than two orders of magnitude than in the known device. Invention Four-square multiplying device containing compensating resistive bridge, in the first and second shoulders of which control resistors are included, and in the third and fourth shoulders fixed resistors, a differential amplifier connected by a non-inverting input to the first vertex of the compensating resistive bridge formed by the first and the fourth shoulders of the bridge, and the inverting entrance to the second vertex of the compensating bridge formed by the second and third shoulders of the bridge, the comparison unit, the source of the reference voltage, first and second low-pass filters, characterized in that, in order to increase the accuracy of work, in multiplying. the device additionally introduces a clock generator, the first, second, third, and fourth keys, and the first, second, and third inverters, the information input of the first key being the input of the first device multiplier, the control input of the first key connected to the output of the clock, information input The second switch is connected to the output of the voltage source, the control input of the second switch is connected to the output of the first inverter, the input of which is connected to the output of the clock generator, the outputs the first and second keys are combined and connected to the third vertex of the compensating bridge formed by the third and fourth shoulders of the bridge, the fourth vertex of the compensating bridge. the bridge is connected to the zero potential bus, the output of the differential usipitett is connected to the information inputs of the third and fourth keys, the third input of the third key is connected to the clock generator, the input of the fourth key is connected to the output of the inverter, the input of which is connected to the output of the clock generator, the outputs of the third and fourth the keys are connected to the pervofo and second low-frequency filter inputs, respectively, the output of the first filter is the output of the device, the output of the second filter is connected to one input of the comparison unit, the other input of which is input to the second factor  798880B devices, the output of the comparison unit under-1. "Instruments and equipment of the experiment are connected to the control input of the primary input. M., 1978, № 4, p. 154-156. controlled resistor and through the third the inverter to the control input of the second 2. Electronic technology in automation. controlled resistor.5 Collection of articles, ed. Koeva Yu. I. Sources of information. 8. M., 1976, p. 25.3-257 (taken into account during the examination of the egypt). / / 5s / / / h / / one/ 7  /  / V.