SU1620949A1 - Device for measuring fluctuations of components of two-terminal network simulator - Google Patents

Abstract

The invention relates to the measurement of the fluctuations of the active and reactive components of simulators of capacitors, varicaps, inductors, resistors, and other bipolar circuits and can be used to study the noise properties of bipolar circuits, as well as screening them. The goal is to increase reliability by providing simultaneous separate measurements of fluctuations of the two-pole imitance components. The device contains a generator of sinusoidal signals 1, a balanced bridge 2, a band-pass filter 3, an amplifier 4, a demodulator 5 amplitude and phase fluctuations, a recorder 6, a phase detector 7, a low-pass filter 8, a reference two-terminal 9, a measured two-terminal 10, a phase shifter 11, reactive element 12, the resistor element 13. 2 Cp f-crystals, 2 Il.

Description

ON

u o yu

1

The invention relates to a technique for measuring the fluctuations of the active and reactive components of simulators of capacitors, varicaps, inductors, resistors, and other bipolar circuits and can be used to study the noise properties of bipolar circuits, as well as to screen them.

The purpose of the invention is to increase the reliability by providing simultaneous separate measurements of fluctuations of the two-pole imitance components.

FIG. Figures 1 and 2 show the structural electrical circuit of the device for measuring fluctuations of the two-pole imitance component components, examples of execution.

A device for measuring fluctuations of a two-pole simulator component comprises a sinusoidal signal generator 1, a balanced bridge 2, a band-pass filter 3, an amplifier 4, a demodulator 5 of amplitude and phase fluctuations and a recorder 6, as well as a phase detector 7, a low-pass filter 8, a reference two-pole 9 the measured two-port 10 and the phase shifter 11. The two-port 9 contains a highly stable reactive element 12 and a resistive element 13 with a variable resistance value.

The generator 1 of sinusoidal signals is sequentially connected to a balanced bridge 2, to the first arm of which a reference two-terminal 9 is connected, and to the second shoulder the investigated two-terminal 10, a band-pass filter 3, an amplifier 4, a phase detector 7 and a low-pass filter 8. 8 low-pass filter output with a controlled input of the reference two-terminal 9, the input of the phase shifter 11 is connected to the output of the generator 1, and its output is to the reference input of the phase detector 7, the input of the demodulator 5 is connected to the output of the amplifier 4, and its output is to the inputs of the two channel Ny registrar b.

A device for measuring the fluctuations of the components of the imigance of the two-pole works as follows.

Generator 1 sinusoidal signals form a signal

lf (t) + dT (t) eJWot, where Eo is the signal amplitude; signal frequency;

5 (t) -vector, determined by relative fluctuations of amplitude Еo and phase of signal EJt). (T) l "1..

The signal E (t) is fed to a balanced bridge 2, the shoulders of which include a measurable two-terminal 10 and a reference voltage; lusnik 9 with imitations Xi, X2, respectively;

0

five

0

X / + 5ai (t) + + dbi (t); (t) + + 5b2 (t); where ai, 32 are active parts of imitations of two-terminal 10 and 9, respectively;

(3 ai (t), d 32 (t) - relative fluctuation components of the active parts of imitances of two-terminal networks 10 and 9, respectively;

bi, 02 - nominal values of reactive elements, which characterize the reactive parts of imitances of two-burned burners 10 and 9, respectively;

d bi (t), 6 02 (t) are the relative fluctuation components of the ratings of reactive elements characterizing the reactive parts of the imitances of two-port 10 and 9, respectively;

P-t-- differentiation operator.

Balance bridge 2 provides modulation of the amplitude and phase of the quasi-harmonic signal of generator 1 due to fluctuations of the in-phase and orthogonal imitation components of the measured two-terminal 10 relative to the imitation components of the reference two-terminal 9. Signal U (t) at the output of the balanced bridge 2

u (t) (t), where d U (t) is a vector defined by relative fluctuations of the amplitude of sig-HanaJJ (t), with U (t) l 1; ;

U is the amplitude of the signal at the output of the balanced bridge 2, represented by a vector, since it has a phase shift relative to the signal at the input with amplitude E (t).

In this case, as follows from the Kirchhoff equation for a balanced bridge 2, the relationship between the fluctuating Q parts of the signal U (t) and imitations of the measured two-terminal 10 is expressed as follows;

2-2 (1 +) Q) 5u (t) bi (t) (t).

WITH

five

0

five

45 where Q

Wrt ai

quality factor measured

-complex dual-terminal 10; + J0ki Ео 1 + JQ balance transfer 2;

ko, ki are the coefficients of the unbalance of the bridge 2 in the active and reactive components of the two-terminal imitance 10,

l ai-82. fc bi-b2. .

K ° 2a2 1 2b2 Band-pass filter 3 separates the signal in the study band of the fluctuations of the two-pole impedance component 10. This signal is amplified by an amplifier 4 and

arrives at the signal input of the phase detector 7 and at the input of the demodulator 5. The fluctuation parts of the signal IT (t) K U (t) at the input of the demodulator 5 and the two-terminal simulation 10

. jL.2 (i) 5i / (t) 5ai (t) + jQdbi (t),

till

where dCr (t) dll (t); K is the total transmission coefficient of the band-pass filter 3 and amplifier 4 (since the band-pass filter 3 and amplifier 4 are made with a negligible phase shift, then K is the scalar value);

Vi

IU.I

Yeo

k2 + Q2H

- module to

1 + Q2 transmission efficiency of balanced bridge 2.

- eJ - ar "9Q phase

ratio of the transfer ratio of the balanced bridge 2.

The phase detector 7, the phase shifter 11, the low-pass filter 8 and the resistive element 13 with a variable resistance value compensate for the unbalance signal of the bridge in the active imitation component of the two-terminal 10 under consideration with respect to the active part of the reference two-terminal 9. The phase-shifter 11 provides a delay of the generator 1 signal the value of arctg Q; In this case, the phase detector 7 compares the phase of the signal of the generator 1 and the signal from the output of the amplifier 4. The output signal of the phase detector 7 after selecting a low frequency hydrochloric moiety lowpass filter 8 is input to rezistiznogo element 13 with variable-resistance value. The zero signal of the output of the phase detector 7 occurs when its input signals are in quadrature, and this is ensured with the bridge balance on the active component of the two-terminal imbuances of 10 and 9. As a result, for two-terminal networks whose simulation is predominantly reactive (capacitors , inductance coils) - Q 1, or active (resistors) - Q 1, the connection of the fluctuation parts of the signal and the imitation of the measured two-terminal 10 is:

2Q ki b iT (t) Q dbi (t) + j (5 ai (t).

The demodulator 5 provides the suppression of the signal with the carrier frequency ob and extracts the fluctuation components of the quasiharmonic signal 1G (t) near the carrier. The demodulation fluctuation components of the signal IT (t) in the outputs of demodulator 5 are equal to:

M0

1 (o-Ygtu-t Tr)

where Ko t - transfer ratio

f T t p

demodulator 5 for the in-phase (am- plitude) f uctuation part of the signal l / (t);

- transfer coefficient

demodulator 5 for the quadrature (phase) fluctuating part of the signal IT (t);

T t-1, P - notch band

L. tflf i i

filter in the input of the demodulator 5; 5iT ()); V0 (t) Ko UF | - -iL-dVoO);

vi (t) KihTi).

If two spectrum analyzers are used as the recorder 6, then the signals that are proportional to the spectral density of the signals at the outputs of the demodulator 5 lV0 (F) iiVi (F) I are formed at their outputs.

In this case, the spectral pg attributed fluctuations of the active and reactive components of the imitance of the measured two-port 10 are associated with the output signals of the demodulator 5 as follows:

(F) mrr-v (ab (p) (p

Considering that ki .. s,

toIN to

(R)

d1 (p) (p).

If the measured bipolar is a capacitor.

5ai (F) dgi (F) (F) 5ci (F), where dgi (F) and dci (F) are the spectral densities of relative fluctuations of conductivity and capacitor capacitance.

If the two-pole device being measured is an inductance coil, then dai (F) 5n (F), 5bi (F) dLi (F), where dn (F) and d C (F) are the spectral densities of the relative fluctuations of the loss resistance and inductance of the coil .

For two-port networks, the imitation of which is predominantly active (resistors) is Q 1, the measurement of fluctuations of the components of the simulations is carried out in a similar way.

The choice of the inductive or capacitive model of the reference two-port depends on the technical implementation and its nominal value.

Claims (3)

Invention Formula 1, A device for measuring fluctuations of a two-pole imitance component, containing a sinusoidal signal generator, a balanced bridge, in the first arm of which a reference two-pole device, including reactive and resistive elements, is connected, the second arm serves as an input for connecting a measured two-pole device, series-connected amplifier, detector and low pass filter, a recorder, characterized in that, in order to increase the reliability by providing simultaneous separate measurements of the fluctuations of the imitation components uhpolyusnika, introduced a bandpass filter, a phase shifter and demodulation fluctuations Torr phase and amplitude, the detector is made phase, the resistive element of the reference two-pole is made adjustable; with the generator output of a sinusoidal signal, and its output with the reference input of the phase detector, the demodulator input is connected to the amplifier output, and its output - with the registrar. 2. The device according to claim 1, 1, which is designed so that, in order to ensure the measurement of two-terminal capacitive type, the reactive and resistive elements of the reference two-pole are connected in parallel. 3. The device according to claim 1, which is designed so that, in order to provide measurements of two-terminal inductive type, the reactive and resistive elements of the reference two-pole are connected in series.