SU1599990A1 - Device for monitoring transmission factor of d-a converter - Google Patents

Abstract

The invention relates to automation and measurement technology and can be used in systems for controlling parameters of digital-to-analog converters. The purpose of the invention is to increase the reliability of control results by eliminating the influence of destabilizing factors while maintaining accuracy. The device for controlling the transmission coefficient of the D / A converter contains the source 1 of the reference voltage, the first 2 and second 3 switches, the output unit 4, the null organ 5, the control unit 6, the voltage divider 7, the recording device 8. Introduction of the feedback element 9, the adder 10 and the DC amplifier 12 achieves a positive effect. 1 il.

Description

The invention relates to automation and measuring equipment and can be used in control systems for parameters of digital-to-analog converters.

The purpose of the invention is to increase the reliability of control results by eliminating the influence of destabilizing factors while maintaining accuracy.

The drawing shows a functional diagram of a device for controlling the transmission coefficient of a digital-to-analog converter.

The device for controlling the transfer coefficient of a digital-to-analog converter contains a reference voltage source 1, first 2 and second 3 switches, an output unit 4, a zero-organ 5, a control unit 6, a voltage divider 7, a recording device 8, a feedback element 9, and an adder 10 °. An output unit 4 made in the form of a low-pass filter 11 and a DC amplifier 12.

The drawing also shows ^ controlled digital-to-analog Converter 13.

A device for controlling the transmission coefficient of a digital-to-analog converter works as follows.

A pulse signal with a duty cycle equal to 2 is supplied to the control inputs of the switches 2 and 3 with the run of the control unit 6; In the position of the contacts of the switches (shown in the drawing), voltage L is allocated at the output of the voltage divider 7; with the opposite position of the contacts of the switches 2 and 3 at the output of the voltage divider 7, a signal D is formed. The input voltage reference of the controlled DAC 13 receives a signal from the output of the adder 10. Signals A, and present in the form:

_{Δ <= [- (U o} + f U () K iy υ _{0 4} (1-κρ] κ _φ; Ί _x 4 = C- _(and rd7 + (1 + Krk _{and about} to _3] to _T1 ] where U about

J5 voltage at the output of the source 1 of the reference voltage; the voltage transfer coefficient of the negative feedback circuit element 9; conversion factor $$ of the controlled DAC 13; the transmission coefficient of the voltage divider 7, made on two resistors;

K is the transfer coefficient of the output unit 4.

Substituting into expression (1) the value of the conversion coefficient of the DAC 13, equal to Kc = 1 + D ^, where D _{c the} error of the coefficient K _c , is obtained at the output of the DC amplifier 12 (taking into account the filtering effect of the output signal of the voltage divider · 7 using filter 11 bass' signal) signal. U ₀ Kq> __ ⁴ 2 +] EC _? By ° _C

From expression (2) it follows, (2) that by supplying a signal to the input of the zero-organ

5, by the output voltage of the latter one can judge the sign of the error of the conversion coefficient of the controlled DAC 13 "

Choosing the value of the transfer coefficient K of the output unit 4 is much larger than unity and setting D _c «1, from (2) get

L = 1 (h)

In accordance with expression (3), the recording device 8 measures the error value of the conversion coefficient of the monitored DAC 13 ..

The introduction of a negative feedback circuit practically does not affect the value of the output voltage proportional to the error of the conversion coefficient of the controlled DAC 13, but at the same time it significantly reduces the influence of destabilizing factors, in particular, instabilities of the output unit 4.

Claims (1)

Claim A device for controlling the transfer coefficient of a digital-to-analog converter, containing a zero-organ, a reference voltage source, the output of which is connected to the first information inputs of the first and second switches, the second information input of the last of which is combined with the same input of the first switch and is an input bus, the control input of the first switch is combined the control input of the second switch and connected to the output control unit outputs the first and second switches are connected co- ⁽ responsibly with the first and second inputs of the voltage divider, the output of which is connected to the input of the output unit, made in the form of a low-pass filter, the input of which is ¹ input of the output unit, characterized in that, in order to increase the reliability of the control results by eliminating the influence of destabilizing factors when preserving accuracy, an adder, an element, feedback, a recording device are introduced into it, and a direct current amplifier, the input of which is connected to the output of the low-pass filter, is inserted into the output unit etc. - it is 5 by the output of the output unit and is connected to the inputs of the null organ, the recording device and the feedback element, the output of which is connected to the front input of the adder, the second input of which is connected to the output of the reference voltage source, and the output is the output bus.