SU1684727A1 - Instrument to meter the rc-, rl-parameters of two-pole network - Google Patents

Abstract

The invention relates to a radio measuring technique and can be used to measure the active R- and reactive C- and L-parameters of a two-port network. The purpose of the invention is to improve the measurement accuracy at the current frequencies and to ensure the connection of the studied two-terminal networks, ifMcmuuix, coaxillaries. The device contains a good quality 1 with a measurable capacitor 2 of the variable OMKonii with kpemmmi 3, an optional inductive element 4, made in the form of a short-circuited two-way line with terminals 5, to which the two-terminal 6 is connected (7). Auxiliary INDUCTIVE BH (MGNT (in the form of short locks (double-wire line or in the form of a x-ray line, on which the terminals are located 5) for connecting the studied two-pole device, located at the maximum distance from its input, can be determined by the formula from the formula that the formula is applied to. . 1 з п. Ф-лы, 1 il. Y (L

Description

Ltd

-U

1st 1

Fig1

316

The invention relates to a radio metering technique and can be used to measure the active R- and resistive C- and L-parameters of two-pole cells.

The purpose of the invention is to improve the measurement accuracy at high frequencies and to ensure the connection of the studied two-terminal networks with coaxial input.

Fig. 1 shows a structural electrical circuit of the device for measuring RC, RL parameters of two-terminal; in fig. Figures 2 and 3 show the connection options for the short stranded two-wire line to the terminals of the measuring capacitor, as well as the connection options for the measured two-pole network to the short-circuited line,

A device for measuring RC and RL parameters of two-terminal devices contains a Q-meter 1 with a measuring capacitor 2 of variable capacitance, with terminals 30 K short-circuited two-wire line 4 with the first and second terminals 5 are connected to terminals 3 for connecting the two-pole 6 (7) under test.

A device for measuring RC, RL parameters of two-terminal devices works as follows

From the theory of oscillatory circuits, in particular, long lines, it is known that the total conductivity of the input resistance of a measuring line is determined by the following expression

from where

1 + tg (I

X

1 8X

AB (1, tgP1, Wjg g

(w, tgp, l, Htf) R "rf

W tgftl. W1W W w,. Wtggl Wtg / 3l

  UgPW.tgft.1,% TsMI W, tgfi, lt aag;

(one

+ C +

Wjtg / 5.1,

W tg filW tgz / YY

 XaS

To simplify settlement operations

T

with Q t y- Yu within the admissible range ZB W

one

za & z

1 + J (W / Za6) -tgfrl W / ZaS + J tgfbl 11

(D

fT J (ri Vrt 1 + 3-) (2) KaЈ (tgfVi as

 aЈ is the impedance at points a, b of the part of the short-circuited line located to the right of the indicated points (length of line 1) with the active loss R of influence and the parameters R and C (L) of the measured two-terminal network; ,, W - wave resistances of measuring line sections with lengths 1 and 1;

f} ,, (3 constant phase shifts of the measuring line

one

Mr & R.

R with lengths It and 1;

L + i

R, R

(3)

Resistance of active losses of the line in parallel replacement, recalculated to points a, resistance of active losses of the measured two-terminal in parallel replacement

five

1 1 1 ArG. HP

(four)

V

D. p - parasitic reactance at points a,% and reactance

measurable two-pole network. From expressions (1) and (2) get

-. (7)

my methodical error in expressions (6) and (7) can be neglected sign5

W2tg2 f5 1 W tg / 3 1 ,, chenii and f.l- f (7

KaЈ K Qg result of which expression (6) will take the form

11i-ty.fli

Rex RaET (1 + WtS3l Wtgfll

 ftar

one

1 Ij.tgfrb

5 Take into account (according to nu ras (3) and (4), that with R oo, u oo (the condition under which the measured two-terminal device is not connected to the terminals 3 of the measuring capacitor

ten

v:

+ Wtg (51 (WttgjfrT

w, tg | Mi Ya {g

 of

RA n G

6X1 + - “--P - (g

In this case, the methodological error of determining RBK and Xg is determined by the length of 1 measuring line section.

Taking into account that at resonance the input reactance of the measurement P

Се С, Ы СК (

OKI / „n -. (Where is IC), QM (O

,eight

the capacitance value of the measuring cone 1 of the degassing device and the quality factor of the oscillatory circuit of the Q Meter (without the measured two-port); when a measured two-pole line is connected, the capacitance resistor 0 to the terminals 3 is equal to the Plasma and the capacitance of the measuring capacitor correspond to the expressions (3) and (4) of the q-factor, from the expression v v L „R - ° kg

/ 04 / GOHA. Chl1 / GTT: K.

(.o; and (9) we have

1 in

R toe ,,

CK ACI YES | cr - it (where CK2, Qic4 is the capacitance of the measuring capacitor and the Q of the oscillatory circuit of the Q-meter while the two-pole device being connected is connected.

w

41-Stil,.) W

aCKV w, tg /5.T (; u tg py teftx

w (i i # LJLL

 - SC

(ten)

So from the expressions

(4), (10) and (11) we have QK.QuO -COCKfW tgfil) 2 (1 O CtczW tg ftp

R G) (ei + tg fil) QK, -CO, CK (W tg | 5l) - .q.w tg / iD

 :

u

1s 1 + tg2 (3 1/13-j

 ea), (CK4-Ck () 0 -DSK, And tg pl) (1 -CO (C ,, 4W

The RC and RL parameters of the bipolar networks are measured as follows.

To the terminals 3 of the measuring capacitor 2 connect the short-circuited line 4, forming an oscillatory system,

Changing the capacitance of the measuring capacitor 2, set the specified oscillatory system into resonance. The resonance moment corresponds to the maximum indicator reading of the Q-meter 1, equal to QK .. Connect the two-terminal 6 (7) to the connecting terminals 5 of line 4 to form an oscillating system: measuring capacitor 2 - short-circuited line 4 - two-terminal 6 (7). By changing the capacitance of the measuring capacitor, the capacitor 2, again adjust the indicated oscillatory system to resonance.

684727

(1 R

aЈ

R

6 W t to, 1

V to

J 1 + tg p

(eleven)

5 Take into account (according to the numerical conditions (3) and (4), that with R oo, u oo (the condition under which the measured two-terminal device is not connected to the terminals 3 of the measuring capacitor

ten

 of

RA n G

and P

Се С, Ы СК (

OKI / „n -. (Where is IC), QM (O

,eight

To the terminals 3, the values of Pa $ and a $ correspond to the expressions (3) and (4) v v L „R - ° kg

HA. Chl1 / GTT: K.

1 in

R toe ,,

CK ACI YES | cg - it (where CK2, Qic4 is the capacitance of the measuring capacitor and the quality factor of the oscillating circuit of the Q-meter with the measured two-port connected.

Thus, from expressions (3),

(12)

The moment of tuning of the oscillating system to resonance corresponds to the maximum indicator of the Q-meter indicator, equal to Qicg- According to the expressions (12 (and (13) determine the active R- and reactive 9Сu components) in parallel with the replacement of the impedance of the two-terminal 6 being measured (7 ).

With a negative value of reactive% and a component of the impedance, the capacitance value of the measured two-terminal is determined by the formula

J

. V

WITH

(14)

and if the reactive value is positive, the inductance component determines the inductance value of the measured two-pole device using the formula

line and connected in parallel konb (71

Case measuring condensate op Q

closed loop coaxial line.

Pus measure the quality factor

Corps isner.

 ondensagora

Fig.Z

Claims (2)

Claim 25 1. Device for measuring KS-, KE-parameters of two-terminal devices, containing a Q-factor meter, which includes a variable capacitance measuring capacitor, the first and second terminals for connecting the two-pole device being investigated, characterized in that, in order to improve the measurement accuracy at high frequencies, He introduced an auxiliary 35 inductive element, which is made in the form of a short-circuited two-wire line and connected in parallel to the end 10 Capacitance measuring housing capacitor with variable capacitance, and the first and second terminals for connecting the tested two-pole device are located on the inductive element at a distance not exceeding the distance from his input, determined by the formula ten ^with 8p _x 1x = 0) C _{K |} ·) (C to - SCG) ^{2 2} °° Yah _No. with _K1 with _K2 (Sk, - SCG) ² 2θ0 to, C, t-} · where K is the distance between the connecting connector and the input of a short-circuited two-wire line; the impedance and phase shift constant of a short-circuited two-wire line with a length of 1 ^; O is the angular frequency of electromagnetic oscillations; " _K , C _K ^ - maximum and minimum the values of the capacitance of the measuring capacitor of variable capacitance, within which the measurement of the parameters of the CS (KB) of two-terminal networks permissible methodical error. 2. The device is pop, distinguished with the fact that, in order to ensure the connection of the studied two-terminal networks with a coaxial input, the inductive element is designed as a short-circuited coaxial line. i.Fig 2 1684727 poo / measure up to 5 m - I to Body dimensions capacitor Fig.Z