SU1341655A1 - Arc=sine digital-to-analog converter - Google Patents

Abstract

This invention relates to automation and computing. The aim of the invention is to expand the range of variation of the argument of the converter. The converter contains three digital-to-analog converters 1-3, three operational amplifiers 4-6, seven large-scale resistors 7-13, and an inverter 14 codes. The principle of operation of the arcsine D / A converter is based on reproducing an approximating expression in the form of a rational fraction represented by a third-degree polynomial relation, which allows the dynamic range of variation of arguments to be expanded by 40%. Additional advantages of the converter are increased accuracy by reducing the approximation error by 20% and increasing the parametric reliability by reducing the sensitivity of the conversion result to variations in the parameters of the elements, 1 sludge. "E (l oo ny with: SP ate

Description

1134

The invention relates to automation and (numeral technology) solves the problem of functional digital-analogue conversion and can be used in specialized devices of information-measuring equipment and automatic control systems.

The purpose of the invention is to expand the range of variation of the argument of the converter.

The drawing shows a functional diagram of the proposed Converter.

The arcsine digital-to-analog converter contains first to third digital-to-analog converters 1-3, first to third operational amplifiers 4-6, first to seventh scaling resistors 7-13, 14 code inverter, scaling voltage input bus 15, code input bus 16

de n n

y 1 2 5

Y,

-input binary code

- reverse input code, (N 1-N);

- weight conductances of digital-analog converters 1, 2 and 3 with the structure R - 2R, respectively;

-conductivity scale resistors 7-13, respectively.

If you bring the expression (1) to the form

Y, -Y

 P

(2)

 Lg - 0.3613; L 0.02922;

  b, 0.5169;

Y

Y

I

Y / y

X i) .X2 LZ 0.03884

five

argument; n (Tfniineit 17 denotes the output transform.

The converter works as follows.

in a way.

The input voltage C ,,, DC is fed to the analog input of the digital-analog converter 1,

and the output voltages of the operational amplifiers 5 and 6 are to the analog inputs of digital-to-analog converters 2 and 3, respectively. Moreover, digital-to-analog converter 1 is controlled by a direct input code, and digital-to-analog converters 2 and 3 are controlled by a reverse input code generated by code inverter 14 ,, the outputs of digital-to-analog converters 1, 2 and 3 are connected to the summing point of an inverting operational amplifier 4. Thus, the transfer coefficient of the converter is

and

-2

five

0

five

0

five

view dependency will be reproduced

uGm - 2i5A l2lN t2i344 iN + 0 93 03- | 0) 0.2697-N + 0.67 85-TO which approximates the function

Z (N) -arcsin 0.98-N with an error of 0.05% with a change in the argument O N 1,

The invention allows to extend the dynamic range of the arcsin digital-analogue conversion by 40% (the prototype reproduces the function Y2 of Z (N) - arcsin --- N). Besides,

The proposed solution provides an increase in the accuracy of the nonlinear conversion by reducing the methodological error by 20%, differs from the known higher parametric reliability due to a decrease in the upper limit of the relative sensitivity functions — the result of conversion to variations of the parameters of the elements.

Claims (1)

Invention Formula Arcsine digital-to-analog converter containing three operas3 seven amplification resistors and two digital-to-analog converters, the first of which is connected by digital input to the input bus of the argument code of the converter, and the output to the inverting input of the first operational amplifier and the first output of the first large-scale resistor, the second output of which is connected to the output of the first operational amplifier and the output of the converter, while the analog input of the second digital-analog converter is connected to the first output of the second large-scale resistor, the output of the second op The amplifier is connected via a third scale resistor with an inverting input of the second opamp and the first output of a fourth scale resistor, the second output of which is connected to the common bus of the converter, and the output of the third operational amplifier is connected to the first outputs of the fifth and sixth scale resistors, and the second output A fifth scale resistor is connected to the inverting input of the third opamp, o t Editor M. Dylyn Order A438 / 53 Tehred M. Didyk Proofreader Circulation 672 Subscription VNIIPI USSR State Committee on affairs of inventions and openings 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, Projecto st., A four L i h i and ii with the fact that, in order to expand the range of the argument of the converter, the third digital-to-analog converter and 1 svertor of the code, the input of which is connected to the input bar of the converter's argument code, are output, and the output is connected to the digital inputs of the second and the third digital-to-analog converters, the outputs of which are connected to the inverting input of the first operational amplifier connected to the non-inverting inputs of the second and third operational amplifiers, while the code of the second operational amplifier connected to the second output of the second scale resistor, the inverting input of the third operational device is connected via the seventh scale resistor to the common converter bus, the analog input of the first digital-to-analog converter is connected to the input voltage scaling voltage of the converter, and the analog input of the third digital-analog converter is connected to the second sixth converter scale resistor. Compiled by I. 1 1. Tehred M. Didyk Proofreader M. Pojo