SU741282A2 - Squarer - Google Patents

Description

one

This invention relates to the field of analog computing and can be used in effective voltage meters.

By bus. St. 634302 a quadr is known which contains a summing operational amplifier, the output of which is the quadrant output, n diode limiters, the first input of each of which is connected to the quad voltage input voltage bus, the second input is connected to the bias voltage bus, and each output The i-ro of the diode limiter (, 2, ..., p-1) is connected to the co-15 by the corresponding input of each subsequent diode limiter and with the corresponding input of the summing operational amplifier, a scaling element, the input of which is connected to the input voltage bus 20 , Quad, and the output - to the corresponding input of the summing operational amplifier .-.

In the case of alternating on-25 arrays with such a quad at frequencies above 1 kHz, a frequency error arises, due to the fact that for each but the first diode the limiter except for the input voltage ZO

voltage is applied from other diode limiters, which are detained by them for different times. Moreover, this error is greater, the greater the number of diode limiters. If their number is small, the approximation error increases.

The aim of the invention is to improve the accuracy of the quad.

This is achieved by introducing a second summing operational amplifier and a nonlinear element into the generator, with one input of the second summing operational amplifier being connected to the quad input, and the remaining inputs connected to the outputs of the corresponding diode limiters, the output of the second summing output amplifier whose output is connected to the corresponding input of the first summing opamp.

FIG. 1 shows a quad pattern; in fig. 2 shows diagrams explaining his work.

Claims (2)

The quadrator contains a summing operational amplifier 1, n diode arresters 2.1,2.2, .., 2.p, the first input of each of which is connected to the quad voltage input voltage bus, the second input is connected to the bias voltage bus, and the output of each i-th diode The limiter is connected to the corresponding input of each subsequent diode limiter and to the corresponding input of summing operational amplifiers 1 and 3, while one input of summing operational amplifier 3 is connected to the input voltage bus, and its output is connected to the input of nonlinear element and 4 (with approximately a quadratic response), whose output is connected to a respective input of the summing operational amplifier 1. Consider the operation squarer, coh yes iviychaks. 1 V, UcN4 - - 1 V. At the same time, the transfer coefficients of diode limiters 2.1,2.2 and summing operational amplifier 3 are equal to V - 1 KCN. 1 2. - T K. -iKJ 2; К -7 4 К - iКо 1 4 With zero input voltage and quadrant output voltage. equals zero. When the voltage Uj changes from zero to -J- The diode limiters are closed by the voltage U., so the voltage U and U are equal to zero the voltage U at the output of the summing control amplifier 3 varies linearly (see Fig. 2), and the voltage at the output of nonlinear element 4 (with an approximately quadratic characteristic) varies approximately by a quadratic law to a magnitude of -16 e. The output voltage of summing opamp 1 repeats the voltage U. J-B opens diode at 2.2 and at 2.2 U change from –r to, B voltage U at its 4 output it changes linearly to --j-B, it. is subtracted from the voltage UB on the summing operational amplifier 3 and leads to a linear change of the Ug voltage by 5t 1 from - –j V to 0. Accordingly, the voltage U at the output of the linear element 4 varies approximately squarely from –r – t B to O. The output voltage UQ of diode limiter 2.2, added to summing operational amplifier 1 with the output voltage U of the nonlinear element, gives a change in voltage UQ ,,, ° Tb ° T ° to approximately quadratic law. When the diode limiter 2.1 opens, When Ug, the diode limiter 2 is closed. 2. As a result (see Fig. 2), a piecewise quadratic approximation of the quadratic dependence on U is obtained. Nonlinear semiconductor resistances (varistors) can be used as a nonlinear element. The maximum reduced approximation error of the proposed quad is reduced compared to the prototype error with the same number of diode limiters by a factor of 1, where cf is the reduced non-square error of the conversion function of the nonlinear element 4. For example, at 6. 5% reduction of the error is. . -.,. 5 times. With the same approximation error, therefore, a smaller number of diode limiters is required, thereby reducing the frequency error. The maximum reduced error of the proposed OT quad, o jw, i.e., the non-quadratic error of the non-linear element SU is reduced by a factor of 2. A quad layout was tested using the proposed scheme with two diode limiters. As a nonlinear element, a quadrant with a piecewise linear approximation with an error of {f 5% was used. The resulting reduced error was about 0.3%, the quadrant according to the prototype bheme with two diode limiters would have an error e-. - and - 1.5%. Quadrator according to avt, eV, 634302, characterized in that, in order to increase its accuracy, a second summing operational amplifier and a nonlinear element are introduced into it, with one input of the second summing operational amplifier being connected to the quad input, and the remaining inputs connected to the outputs corresponding diode stops, the output of the second summing operational amplifier is connected to the input of a nonlinear element, the output of which is connected to the corresponding input of the first summing operational amplifier tel.