SU1762264A1 - Converter of parameters on untuned three-component three-terminal networks to voltage - Google Patents

Abstract

Use: instrumentation for automatic measurement of parameters of a three-port network. The device contains: a shaper 1 of the reference voltage, two supporting elements 2.3, two operational amplifiers 4.5, two differentiators 6.7, a limiter 8, an integrator 9. two dividing units 10.11, and a multiplication unit 12, a three-terminal 13 under study is a series connection of the capacitor 14 and the parallel circuit of the capacitor 15 and the resistor 16. By forming the output voltages simultaneously with the start of the shaper, the speed of the device is increased. 2 sludge.

Description

The invention relates to instrumentation engineering and can be used to automatically measure the parameters of a three-element three-port network.

The aim of the invention is to increase the speed of the converter.

Fig. 1 shows a structural diagram of the proposed converter: in Fig. 2, timing diagrams explaining its operation.

The converter of parameters of nonresonant three-element three-pole circuits to voltage contains a driver 1 of the reference voltage, support elements (resistors) 2 and 3, operational amplifiers 4 and 5, differentiators 6 and 7, limiter 8, integrator 9, blocks 10 and 11 divisions and block 12 multiplication . The input of the driver 1 is connected to the starting bus, and the output through a resistor 2 with the inverting input of the amplifier 4, the non-inverting input of which is connected to the common bus, and the output to the input

The differentiator 6. The input of the differentiator 7 is connected to the output of the differentiator 6, with the second input of the block 10 and the first input of the block 11, and the output to the second input of the block 11 and the input of the limiter 8 connected by its output with the input of the integrator 9, the output of which is first output converter. Resistor 3 is connected to the feedback circuit of amplifier 5, the non-inverting input of which is connected to the common bus and the output to the first input of block 10, the output of which is the second output of the converter. The first and second inputs of block 12 are connected to the outputs of block 11 and integrator 9, respectively.

The three-port 13 under study, which is a series connection of a capacitor 14 and a parallel circuit consisting of a capacitor 15 and a resistor 16, is connected to the inverting input and output of the amplifier 4, respectively, and the third output to the inverting input of amplifier 5.

J

xj

; 0

hO

yoo o

,

The Converter operates as follows.

By the Start command, coming over the start bus, the shaper 1 is started. A positive voltage jump of a constant level E appears at the output, which through a 2G resistor equal to R0 enters the input of the amplifier 4, - to the feedback circuit of which a capacitor 15 with a capacitance Ci and a resistor 16 whose resistance is equal to H,

The voltage Ui (t) at the output of amplifier L, as a function of the time t, counted from the moment of starting the driver 1, can be written as

Ui (t) fd-e-4)

voltage

 p D RoCi (1 e

) Is

Us (t) voltage

Ua (t) .. roRCt

(3)

ten

15

20

where Ge2 is the time constant of the differentiator 7.

The voltage K3 (1) (Fig. 2, c) has a positive polarity, therefore it does not pass through the limiter 8 to the input of the integrator 9. The short pulse of negative polarity passes through the limiter 8 to the input of the integrator 9 and integrates last. At the output of the integrator 9, the voltage U4 of the negative polarity of a constant level, defined by the equality

The voltage u1Y (Fig. 2, a) goes directly to the input of a 6 l differentiator through a capacitor 14 with a capacity of Ca to the input of the amplifier 5.

Differentiator 6 differentiates the input voltage at its input. At its output, an iteration is formed (Iteft), defined by the equation:

and)

where GE1 is the time constant of the differentiator 6.

In view of equation (1), we obtain:

U2 (t)

Ro ci

Ex1 RoCi

+

Ex1 RoCi

(one )

The voltage U2 (t) (Fig.2,6) is fed to the input of the differentiator 7, to the second input of the block 10 and to the first input of the block 11.

Differentiator 7 differentiates the input voltage at its input. The voltage at the output of differentiator 7 is the sum of the reactions of differentiator 7 to negative ska. Exe1 amplitude voltage

chock

voltage

Erai

(1 - his

RoCi

), Reaction

RoCi

The differentiator 7 on the voltage surge is a voltage pulse of negative polarity and of very short duration. The reaction of differentiator 7 on

and

and on

and

and E G1 82 Sh - g

RO Cl Ti

(four)

25

thirty

35

40

where TU is the integrator time constant 9.

The voltage 1M (Fig. 2, d) is fed to the first output of the converter and to the second input of unit 12. It is easy to see that it is uniquely associated with the parameter Ci of the studied two-port network.

The amplifier 5, together with the capacitor 14 in the input circuit and the resistor 3, whose resistance is equal to Ro, in the feedback circuit form an inverting differentiator with a time constant of RoC2. The voltage Us (t) at its output is determined by

 UKD-RoCz- lM

In view of equation (1), we obtain: 45 U5 (t) (5)

Ci

50

The voltage U5 (t) (Fig.2, d) is fed to the first input of the block 10.

Block 10 divides signals Us (t) and U2 (t). entering his first and second entrances. At its output, a voltage Ue is formed, determined by the equality

55

U6

Us (About OTGO

Taking into account equations (5) and (2) we get

ii RO Ue r-C2

GE1

The voltage Ue (Fig.2, e) goes to the second vy-. converter It is easy to see that it is uniquely associated with the Cg parameter of the two-port network being investigated.

Unit 11 performs the division of the signals (t) and Usft arriving at its first and second inputs. At its output, a voltage U is formed. It is defined by the equality

IMP TSCHT)

Taking into account equations () and (3) we get RCi

The voltage U is fed to the first input of block 12,

Block 12 multiplies the signals U and LU at its first and second inputs. At its output, a voltage Us is formed, defined by

U8 U7-tM.

Taking into account equations (7) and (4) we get

U8

Ete ro

R

The voltage Us (Fig.2, g) is fed to the third output of the converter. It is not difficult to see that it is uniquely associated with the parameter R of the studied two-port network.

Thus, on the first, second, and third outputs of the converter, the voltages U, Ue, and Us are formed, the levels of which are uniquely related to the parameters Ci, € 2, and R of the three-port circuit under study. Moreover, as can be seen from the time diagrams (Fig. 2, d, e, g), these voltages are formed simultaneously with the launch of the imaging unit 1.

It should be noted that, in the prototype converter, the required voltage levels are set only after the expiration of the time period T 6RC2 for the former driver, This leads to the conclusion that the performance of the proposed converter is much higher than that of the prototype converter.

Claims (1)

10 Formula invented and The converter of parameters of nonresistant three-element three-terminal circuits into a voltage containing a sequentially connected driver of the reference voltage of the 15, the input of which is connected to the starting bus, the first supporting element; the first operational amplifier, two differentiators, a limiter and an integrator, the output of which is the first output 20 converter, and the non-inverting input of the operational amplifier is connected to a common bus, which is distinguished by the fact that, in order to increase the speed of the converter, a second operational amplifier, a second reference element, the first and second division blocks and the multiplication unit , the second supporting element is included in the feedback circuit of the second operational amplifier, the first 30, the input of the first division unit is connected to the output of the second operational amplifier, the second to the output of the first differentiator, and the output is the second output of the converter; the first and second inputs of the unit 35 divisions are connected to the outputs of the first and second differentiators, respectively, and the output is connected to the first input of the multiplication unit, the second input of which is connected to the output of the integrator, and the output of the smart block 40 is the third output of the converter, and the inverting input of the second operational amplifier is connected to the common bus, The first output of the studied two-port network is connected to the inverting 45 with the input of the first operational amplifier, the second output with its third output, and the third output with the inverting input of the second operational amplifier. 15) l J