SU1622858A2 - Device for measuring parameters of microcircuits - Google Patents

Abstract

The invention relates to instrumentation technology and can be used to measure the parameters of superheterodyne receiver chips, in particular, as part of an automated control system. The aim of the invention is to expand the functionality due to the possibility of measuring the new parameters of the control object in the frequency-modulated mode and improving the measurement accuracy due to the possibility of stabilizing the input level of the specified effects. 1 il.

Description

The invention relates to the development of instrumentation for measuring the parameters of superheterodyne receiver chips, can be used in batch production as part of an automated control system and is an improvement of the invention according to the author. R 105789J.

The aim of the invention is to extend the functionality of additional measurement of an object's parameters to control the increase in measurement accuracy due to the possibility of stabilizing the input levels of specified effects while eliminating the variation of the input parameters of the control object.

The drawing shows a diagram of the proposed device.

The device contains low 1 and carrier 2 frequency generators, amplitude modulator 3. first attenuator 4, contact block 5, microcircuit 6 to be measured 6, frequency generator 7, frequency limiter 8, first frequency divider 9, first phase detector 10, second frequency divider 11, second limiting amplifier 12, switch 13, first integrator 14, direct current amplifier 15, local oscillator electronic tuning element 16, mixer 17, first low-frequency filter 18, matching amplifier 19, alternating voltage meter 20, adjustable amplifier 21, harmonic coefficient meter 22, voltage detector 23, first comparison element 24, second integrator 25, DC amplifier 26, voltage source 27, third divider, 28 frequencies, second phase detector

29, second low-pass filter 30, adder 31, voltage controlled oscillator 32, programmable division divider 33, third limiting amplifier 34, third low frequency filter 35, adjustable gain stage 36, high frequency amplifier 37 , second attenuator 38, cascade 39 with adjustable transmission coefficient, switch 40, power amplifier 41, detector 42, third integrator 43, second comparison element 44.

The low-frequency generator 1 is connected to one of the amplitude modulator 3 inputs and an attenuator 38. The carrier frequency generator 2 is connected to the second input of the amplitude modulator 3, the output of which is via a variable gain stage 39, a power amplifier 41, an attenuator 4 is connected A terminal of the contact block 5 corresponding to the input of the measured chip 6. The terminal of the contact block 5 corresponding to the output of the low frequency of the microcircuit is connected to the alternating voltage meter 20 and the input of the adjustable amplitude 21, the output of which is simultaneously connected to the measured 22 harmonic coefficients and the input of the detector 23 of the effective voltage value, the output of which is connected to one of the element inputs, 24 comparison, the output of which is connected to the control input through the integrator 25 and the amplifier 26 adjustable amplifier 21. The reference input of the element 24 is connected to the source 27 of the reference voltage and the reference input of the comparison element 44, the other input of which through the detector 42 is connected to the output of the power amplifier 41 and the input of the attenuator 4. The output of the electric 44 through the integrator 43 is simultaneously connected to the control inputs of the cascades 39 and 36. The output of the cascade 36 is connected via a high-frequency amplifier 37 to a commutator 40, and its input is connected to the output of a low-frequency filter 35, the input of which is connected to the output of the generator 32. and the input of the limiting amplifier 34 whose output is connected via a frequency divider 33 to one of the inputs

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15

20

25

622858l

phase detector 29, the output of which through the low-frequency filter 30 and the adder 31 is connected to the input of the voltage controlled generator 32, the second input of the adder 31 is connected to the output of the attenuator 38. The second input of the phase detector 29 is connected to the output of the frequency divider 28, the input of which is connected to the output of the amplifier-limiter 8 and the input of the frequency divider 9, the output of which is connected to one of the inputs of the phase detector 10, the other input of which is connected through the frequency divider 11, the limiting amplifier 12, the movable contact of the switch 13; ohm contact block 5 corresponding to the output of the intermediate frequency amplifier of the measured chip 6. The output of the local oscillator of the measured chip through the corresponding contact of the block 5 is connected via a matching amplifier 19 to the input of the mixer 17, to the other input of which the generator 7 of the reference frequency and the input of the limiting amplifier 8 are connected The output of the phase detector 10 through the integrator 14, the amplifier 15 of the direct current and the element 16 of the electronic tuning of the local oscillator is connected to the corresponding output of the chip through the contact block 5. The low frequency output of the mixer 17 through the filter 18 is connected to the normally open contact of switch 13.

The operation is carried out in two modes: measurement of the parameters of the microcircuit in the mode of amplitude-modulated oscillations (AM mode); Measurement of microcircuit parameters in the mode of frequency-modulated oscillations (FM mode).

The AM mode corresponds to the reception of medium waves (MW) and is monitored at an input frequency of 1 MHz.

FM mode corresponds to the reception of ultrashort waves (VHF) and due to the fact that a number of chips used in this mode with an external frequency converter, it corresponds to the conversion of the intermediate frequency-modulated frequency into low-frequency oscillations.

The mode of operation of the device is selected by an external influence on the switch 40 and block 5, which contains all the mounted elements necessary for the operation of the chip in a given mode of operation, including resonance 30

35

40

45

50

55

five . circuits tuned to specified intermediate frequencies.

Consider the work when measuring parameters in the mode of amplitude-modulated oscillations.

The following components are used in the measured microcircuit: local oscillator, mixer, intermediate frequency amplifier, detector, low frequency amplifier.

Carrier 2 and low frequency 1 generators form amplitude modulated oscillations using an amplitude modulator 3

U, (t) - UMSin 2fiF4 t l + + (Cos 2tot)

where n is the modulation depth;

Uc is the amplitude of the carrier voltage; Ft - carrier frequency

generator frequency 2; Q is the frequency of the modulating oscillations of the generator 1. This signal enters through the cascade 39, the switch 40 and the power amplifier 41 to the input of the attenuator 4 and the detector 42, the output of which is a voltage

and a, - wet ,,,

TO

four(

TO

42

where the transmission coefficient of the adjustable cascade 39; K - transfer coefficient of the switch 40, K4C 1; 4, - the transfer coefficient of the power amplifier 41; 42 conversion factor

alternating voltage to a constant with detector 42. The output voltage of detector 42 is compared with the reference voltage value of source 27 using a comparison element 44, the difference is amplified and integrated by integrator 43 and acts on the cascade 39 in order to reduce the error of the error, i.e. . the attenuator 4 is supplied with a voltage equal to U4 (Uj (t)

K ,, (U3o - Uen) .K4tLK4.

This voltage using attenuator 4 is conducted to the input of the microcircuit, i.e.

2858

Uk kl

five

where K4 is the attenuation factor of the attenuator 4.

Thus, the input signal is generated in the mode of amplitude-modulated oscillations.

The local oscillator of the measured microcircuit produces a voltage with a frequency RG, which is mixed by the mixer of the microcircuit and converted into an intermediate frequency voltage F ,,.

5 of the difference between the frequencies of Phy F. Due to the scatter of the parameters of the measured microcircuits, it is necessary to automatically adjust the microcircuit to the measurement mode. This is done by adjusting the frequency of the local oscillator depending on the value of Fr - F, reducing it to a given value of Fn «465 kHz.

Depending on the position of the switch 13, the trimming circuit is implemented in two ways: the first is based on the selection of the intermediate frequency at the output of the chip, the second - on the selection of the intermediate frequency using the mixer 17 and the filter

0 18 low frequency. In the second case, the possibilities are expanded, as it is possible to analyze the receiver bandwidth by measuring the frequency of the carrier-frequency generator 2.

In either case, the intermediate-frequency voltage is fed through amplifier-limiter 12, frequency divider 11 to the input of phase detector U, to another input that the signal from generator 7 of the reference frequency through the first frequency divider 9 and amplifier-limiter 8.

In the steady state we have

-LL

to.

lSL

44

Wed,

where F is the frequency of the signal generator PA-7;

K, K, is the division ratio of frequency dividers 9 and 11; FC- is the frequency of phase detection of the detector 10. The voltage from the output of the phase detector 10 through the integrator 14 and the DC amplifier 15 controls the operation mode of the element 16 of the local oscillator,

the value of the heterodyne of the chip 6 through the contact block 5. Thus, the intermediate frequency is stabilized by changing the frequency of the input signal or changing the samples of the chip during the measurement process.

The low-frequency output level of the microcircuit is measured by an alternating voltage meter 20 and through an adjustable amplifier 21 is fed to the input of the harmonic coefficient meter 22.

Adjustable amplifier 21 in conjunction with voltage detector 23, comparison element 24, integrator 25, DC amplifier 26 connected to the control input of adjustable amplifier 21, and reference voltage source 27 maintain a constant voltage level. At the input, the harmonic meter 22 is independent of the output level of the microcircuit, which can vary from sample to sample.

Thus, in the AM mode, by changing the modulation depth (the output voltage level of the low-frequency generator 1), you can measure the output voltages for a given modulation depth and input action values (attenuator 4), harmonic ratio for given input signal levels and modulation depth, as well as signal-to-noise ratio.

The measurement is carried out with a modulation depth equal to zero (noise voltage measurement), and then at a predetermined modulation depth.

Changing the amplitude of the voltage supplied to the adder 31 using an attenuator 38, you can change the frequency deviation of the frequency-modulated signal. By changing the division ratio of the divider 33, the center frequency of the signal can be changed. The measurement of the harmonic coefficient is carried out at the input FM loop with the specified parameters by the meter 22. The output voltages with different modulations are measured by the meter 20 (voltmeter).

The measurement of the signal-to-noise ratio in the FM mode is carried out in three stages, the measurement of the output voltage with a voltmeter 20 with the input signal parameters (); measurement

output voltage with a voltmeter 20 in the absence of FM modulation (Ugfl);

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finding the ratio of N 20 lg

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0

5 5

0

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0

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The introduction of a circuit to maintain a stable voltage level at the input (blocks 37, 36, 40, 41, 42, 44 and 43) leads to an increase in accuracy, and the creation of a master oscillator with stabilization of the center frequency signal (blocks 7, 8, 28, 29 , 33, 34, 30, 31, 32, 35, 36, 37, 38, and 1) expands the functionality of the proposed device.

Claims (1)

Invention Formula Device for measuring the parameters of microcircuits auth.St. P 1057893, characterized in that, in order to expand the functionality and improve the measurement accuracy of the parameters of the superheterodyne receiver chips, a second attenuator, a third limiting amplifier, a third frequency divider, a third integrator, a second and third low-pass filters, a second element of comparison are introduced into it , adder, generator, voltage controlled, divider with programmable division ratio, first and second stages with adjustable transmission coefficient, high frequency amplifier, switch, amplification power indicator, a detector whose input is connected to the output of the power amplifier and the input of the first attenuator, and its output to the first input of the second reference element, the second input of which is connected to the reference voltage source, the output of the second comparison element through the third integrator connected to the control inputs The first and second stages with an adjustable transmission ratio, the output of the first stage with an adjustable transmission coefficient is connected via a high-frequency amplifier to the first input of the coyug / tator, the second input of which is connected to the output of the second stage with an adjustable transmission coefficient, the input of which is connected to the output of the amplitude modulator, the output of the combi-generator is connected to the input of the power amplifier, the input of the third frequency divider is connected to the output the first limiting amplifier and the input of the first frequency divider, the output of the third frequency divider is connected to the first input of the second phase detector, the output of which is connected through the second low-pass filter to the first input of the adder, whose output is connected to the inputs through a voltage controlled oscillator the third low-pass filter and the third limiting amplifier, whose output through a divider with a the graded divide factor is connected to the second input of the second phase detector, the output of the third low-frequency filter is connected to the first input of the first stage with an adjustable transmission ratio, the input of the second attenuator is connected to the output of the low-frequency generator and the input of the amplitude modulator, and its output to the second input adder.