SU1601748A1 - Variable active two-pole network simulating impedance - Google Patents

Abstract

The invention relates to electronics. The purpose of the invention is to increase the accuracy and expand the range of the simulated impedance. An adjustable dvukhpolosnik imitating impedance contains an adjustable multi-pitch 1, consisting of an adjustable differential amplifier (RC) 6, algebraic adders 2 and 3, and exemplary elements 4 and 5. By controlling the transfer ratio of the DV 6, you can get different impedance values at the inputs adjustable active two-port. Exemplary elements 4 and 5 can be resistors, inductances and capacitances, the values of which should be equal. In the case of variations in the denominations of model elements 4 and 5, compensation is possible by selecting the transfer coefficient, which should not exceed 1, algebraic adders 2 and 3. To reduce the error introduced by the input resistance of the adjustable multipole 1, voltage repeaters with a large input impedance. 4 hp f-ly, 4 ill.

Description

Second entrance

Fy

The invention relates to radio electronics and can be used in tunable filters, attenuators of adjustable amplifiers.

The purpose of the invention is to increase the accuracy and expand the range of the simulated impedance.

Figure 1 shows a structural electrical circuit of a regulated active two-pole device simulating impedance; figure 2-4 - the same options. I Adjustable active dvukhpolisnik, Imitating impedance, contains an adjustable multipole 1, first 2 and second 3 algebraic sum- (tori, first 4 and second 5 exemplary elements), adjustable differential amplifier 6, differential amplifier {7, digital-analogue converter 8, (The first 9 and second 10 controlled attenuators are jaTOpbt and the first 11 and second 12 multiply i digital-to-analog converters. The two-port works as follows.

; If the resistances of the first and second: exemplary elements are the same, the equivalent resistance between the first and second terminals of the device is determined by the expression

2e

ZSKB -

Kv

where Zo3 is the resistance of the model element;

Ku - the differential gain of the differential amplifier .-

Active Nekv. the inductive UKB and capacitive seq components of the simulated resistance correspond to the expressions

POE

Neke -

Ku

from

Sakw Soe Koo; where Boe, {-oe m Soe-respectively active.

inductive and capacitive components of the resistance of the reference element.

The voltage at the output of the differential amplifier 6 is equal to

UAy- (U2-Ul) Ky,

where Ui and U2 are the voltages relative to the common wire, respectively, on the first and second terminals of the device;

Ku - the transfer coefficient of the differential amplifier,

The output voltage of the first algebraic adder 2 is equal to

Uci Ui + Oud - Ui + (U2 - Ui) Ku.

The voltage at the output of the second algebraic adder 3 is

UC2 U2 - Oudu U2 - (U2 - Ul) Ku.

The stresses, respectively, on the first 4 and on the second 5 exemplary elements are equal

Uo3i Ui - Uci Ui - Ui - (U2 - Ui) Ku (Ui-U2) Ky;

Uo32 U2-Uc2 U2-U2 + {U2-Ul) Ky (Ui - U2) Ky.

The currents flowing respectively through the first 4 and the second 5 exemplary ames are equal to

, Uo3i (Ui -U2) Ky

 Zo3l

Uo32 (Ui -U2) Kv. Zo32Zo32

where Zo3i and Zo32 are the resistances of the first and second exemplary elements, respectively.

If Zo3i Zo32 Zo3, then the current flowing from the first output to the second is equal to

| „|„. ,, ,, (C -) D.

i-O3

Then the equivalent resistance between the first and second terminals is

U2 UT-U2

1z2

(Ul-u2) Ky / Zo3

 Ui

Z3KB

 Zo3

Ku

By controlling the gain of the differential amplifier, different impedance values can be obtained at the outputs of the adjustable active two-pole network. Moreover, exemplary elements 4 and 5 can be both resistors and inductances and capacitances, the values of which should be equal. If the nominal values of the model elements are scattered, it can be compensated by selecting the ratio of the transfer ratio of the first and second algebraic adders 2 and 3, respectively, from their first summing input and subtracting input, their transfer coefficients of adders corresponding to MX of the second summing input should be slightly less than one to exclude excitation of the device.

When using the device of figure 2, the transmission coefficient of the adjustable multipole is equal to

 to

Where

KDM -

chrmg-,

where N is the number of value applied to the control input of a digital code;

NMSKC - the maximum numerical value of a digital code;

Cd is the gain module of the differential amplifier 7.

Then the equivalent resistance between the first and second pins of the adjustable active two-port in figure 2 is equal to

2 eq -

- Zo3 Mmax Kdu N

With a ten-by-one digital-to-digital converter and the use of capacitors as model elements 4 and 5 with a capacity of 100 μF, the adjustable active two-pole has a range from 0 to 100 μF with a resolution of 0.1 μF.

When executing the device in FIG. 3 and

4i if the resistances of the first 4 and second

The 5 standard elements are identical and the transfer coefficients of the first 9 and second 10 controlled attenuators are the same; the equivalent resistance between the first and second terminals of the device is determined by the expression

  1 - Catt

where Zo3 is the resistance of the model element;

Catt is the transfer coefficient of the controlled attenuator.

When performing variable attenuator 1 on digital-to-analog converters 11 and 12, their transfer coefficient corresponds to expression 1 - N

1JajTj,

1x max

where N is the numeric value of the digital code supplied to the digital-to-analog converters;

NMBKC is the maximum numeric value of the digital code at the control input.

Therefore, in this case, the expression

Zo3 Zo3 NMBKC

2 eq -

1 N

N

Max

N

The adjustable active two-poles of FIGS. 2 and 4 are different in that the first has the maximum value of equivalent resistance when the code is zero at the control input and the second at the maximum code at the control input.

The spread of the transmission coefficients of the controlled attenuators 9 and 10 and the digital-analog converters 11 and 12 can be compensated for by changing the transmission coefficients of the algebraic adders 2 and 3 from their respective inputs. To reduce the error introduced by the input resistance of the adjustable multipole 1, voltage repeaters can be installed at its inputs

large input impedance. And as digital-to-analog converters 8, 11 and 12, only multiplying digital-to-analog converters with a resistive matrix R -2R can be used.

Claims (5)

1. Adjustable active two-pole impedance imitation containing an adjustable multipole, first algebraic adder, first exemplary element, the first output of which is the first input of an adjustable 15 two-pole imputant imitating, characterized in increasing the accuracy and extending the range of the simulated impedance introduced 20, the second exemplary element, the second algebraic adder, the first and second inputs of the adjustable multipole are the first and second pins of the adjustable active two-terminal imitating 5, the impedance of the adjustable multipole is connected to the first summing input of the first algebraic adder and the subtractive input of the second algebraic adder, and is 0 the output of the adjustable multipole, the outputs of the first and second algebraic adders are connected respectively to the second pins of the first and second exemplary elements, and the first 5 the output of the second exemplary element is connected to the second input of the adjustable multipole, and the second inputs of the first and second algebraic adders are connected respectively with the first conclusions 0 of the first and second exemplary elements. 2. Bipolar according to claim 1. characterized in that the adjustable multipole is designed as a variable differential amplifier, the inverting input of which is the first input of the adjustable multipole, the second input of which is non-inverting. tatting input adjustable differential amplifier whose output 0 is the output of an adjustable multipole. 3. A two-port network according to claim 1, characterized in that the adjustable differential amplifier is designed as 5 series-connected differential amplifier and multiplying digital-analogue converter, the output of which is the output of an adjustable differential amplifier, and digital inputs of the multiplying digital-analogue amplifier The transducer is the control input to an adjustable differential amplifier. 4. A two-port device according to claim 1, characterized in that the adjustable multi-terminal is made in the form of two controlled attenuators, the inputs of which are connected respectively to the first and second inputs of the adjustable multi-terminal, and the outputs of the first and second attenuators are connected respectively to the first and second output of the multi-terminal, its outputs are connected respectively with the first summing inputs of the first and second algebraic adders and the subtractive inputs of the second and first algebraic adders, and the second summing inputs the first and second algebraic adders are connected respectively to the second and first inputs of the adjustable multipole, the control inputs of the first and second controlled attenuators are combined and are the control input of the adjustable multipole. 5. A two-port device according to claim 1, characterized in that the adjustable multi-terminal is made in the form of the first and second multiplying digital-to-analog converters, the analog inputs of which are connected respectively to the first and second input of the adjustable multi-terminal, and outputs. direct and inverse current of the first and second digital-to-analog converters are connected respectively to the first, third, fourth and second outputs of the controlled multi-terminal, and the first and The second summing inputs of the first and second algebraic adders are connected respectively to the first, second, third, and fourth outputs of the adjustable multi-terminal, and the Digital inputs The first and second digital-to-analog converters are combined and are the control inputs of the adjustable multi-port. management faye. 2 Bxod u renewal Fiel