SU1410066A1 - Digital-to-phase function converter - Google Patents

Abstract

The invention relates to analog-digital computing and can be used in combined computing devices and automatic control systems. The purpose of the invention is to increase the accuracy and simplify the setup of the device. The code-phase converter contains three adders 1,2,3, two multiplying digital-to-analog converters 4 and 5, an inverter 6, two inputs for setting reference voltages 7 and 8, an input code bus 9, and an output 10. The conversion is performed by weighted summation voltages, the required weights K, and KJ, which are functions of sine and cosine of the input code, are approximated by second-order fractional rational fractions. 1 Il. (L

Description

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The invention relates to the field of analog-digital computing and can be used in computer, binned computer devices and automatic control systems.

The purpose of the invention is to improve the accuracy and simplify the setting. The drawing shows the functional scheme of the device, the Converter contains the adders 1 3, multiplying digital-to-analog converters 4 and 5, the inverter 6, the first and second inputs of the reference 15 voltage 7 and 8, the code bus 9. and the analog output 10,

Functional converter code-phase works as follows.

The bus 9 is supplied with the digital code N, 20 to the inputs 7 and 8 - the reference voltages. The principle of operation of the device is based on the weighted sum of the two sinusoidal voltages shifted in phase. One relative to the other 25 by 90.

Input 7 is signaled

Uo4 itk-cosujt. (1)

Input 8 is signaled

Uo U ", a." Sinwt. X2) 30

In the circuit diagram of the device, single-phase coding is used, in which the binary code is fed to the digital inputs of both multiplying digital-analogue converters 4 and 5. 35

The magnitude of the output signal of the converter is described by the ULIGC equation 1, cosu.t + K., U ,. sintvt

U ... sin (.. t + 4),

(3)

where K and Kj. weight functions

signals, equal K, -, (4) Kj, cos ff / 2-N, (5) where N is the input code.

The weighting factors K, and K, j in the converter are approximated by functions in the form of second-order rational fractions.

T7 / m - afNj: b.N: .l-N) i. . . F, vN) -. i, .N. (t-N), V.

, .... a-C (1-N) + b.N (1-N). , (N) -: iZ - 5 i N) - - -.

where ajbjC are the coefficients of an anxiety function ,,

With the most complicated Chebyshev approximation of functions (6) 5 (7) to dependencies

(4), (5) we obtain the following values of the coefficients:

, 002; , 555; , 3867. (8) Consider operating the device separately, first only when the first reference voltage (1) is applied to input 7, and then when the second reference voltage (2) is applied to input 8 and the output voltage Uj and U is found in both cases, we get the general formula of the converter, as a superposition of these results

Mr. I.L.

and cosa, + 1-КмК.ГМ-КК, К „.К ,, - М

4 .sin..t i - SijKj.cKa yl: NiK3; Ka.Ki,

 l-K ,,., jK «N | . . Here are the transfer coefficients of the i-ro element of the circuit (see drawing).

Comparing expressions (9) and (3) with regard to (6), (7), one can see that a one-to-one correspondence is fulfilled under the following conditions

1-f (2 L 11 I

li 32

(ten)

Then the values of the parameters of the simulated functions will be expressed in terms of the transmission rates of the elements of the functional circuit of the device in the following way:

, | J-, / К „; ,, (eleven)

These expressions are simpler than the prototype, they allow to simplify the calculation of the device and reduce the mutual influence of the transmission coefficients K;, on the parameters a, b and with the approximating expressions

In order to ensure the best approximation of the approximating functions to the required transfer factors, K - taking into account (8), (10), (11), should have the values:

K ,,, a 1,002;

, 556; (12)

K., 3867;

,,,

The coefficients Kn, K, and Kj can be taken equal to one, which will introduce a relative error of approximately 0.2%,

This simplifies the adjustment of the converter and the setting of the required transmission coefficients, since the existing technology of obtaining the same resistors in miasroelectronics (or using resistor arrays of the 308, 309 series) allows

3

setting transmission coefficients with high accuracy (not worse than 0.02%). Thus, a more careful fit will require only three transfer coefficients of the adder 2.

Claims (1)

Invention Formula  The functional code converter is a phase containing the first, second and third adders, the first and second digital-to-analog converters, the analog inputs of which are connected respectively to the outputs of the first and second adders, the first inputs of which are connected respectively to the inputs of the first and second reference voltages of the device, the first and the second inputs of the third adder are connected respectively to the outputs of the first and second multiplying digital-to-analog converters, The device input code bus is connected to the digital input of the second multiplying digital-to-analog converter, the output of which is connected to the second input of the first adder, the output of the third adder is an external device and connected to the second input of the second adder, characterized in that, in order to improve accuracy and simplify settings, an inverter is entered into it, the input of which is connected to the input of the second reference voltage, and the output is connected to the third inputs of the first and third adders, the input of the first reference voltage the voltage is connected to the third input of the second adder, the digital input of the first multifunction digital-to-analog converter is connected to the input code bus, the device.