SU1390810A1 - Device for measuring amplitude-frequency characteristics of four-terminal networks - Google Patents

Description

(21) 4173323 / 24-09

(22) 01/04/87

(46) 04.23.88. Bul No. 15 (72) G.V.Prosvirov, R.P.Sapogov, L.V. Filipov, and E.I. Shabakov (53) 621.317.84 (088.8) (56) Instrument for the investigation of amplitude-frequency characteristics XI-50 Technical description and operating instructions 2.048.062: 10, 1982.

(54) DEVICE OF MEASUREMENT OF AULLITUDE-FREQUENCY CHARACTERISTICS OF FOUR-POLES

(57) The invention relates to radio engineering. The purpose of the invention is to determine the accuracy of the measurement. The device contains modulating voltage block 1, indicator 2, oscillator 3 oscillating frequency generator 4 clock pulses, binary counter 6, block 7 hours

with so

about

00

total marks, electronic board 8, electronic keys 9, 10 and 14, amplifier 15, decoder 16. Researched quadrupole (ICH) 17, Memory block 5, amplitude selector (AC) 11 and 12, delay line 13 are entered. The time constant of line 13 is equal to the period of the following clock pulses, which ensures that the next and previous pulses from the pulse sequence simultaneously arrive at the first and second inputs of the AC 11, respectively. AC 1 1 ocyniec- selects the pulse with the maximum amplitude from the entire pulse sequence. The amplitude of this pulse corresponds to the maximum value of the frequency response number 117,

one

The invention relates to radio engineering and can be used to simultaneously measure the amplitude-frequency characteristic of a four-pole network and its passband,. The purpose of the invention is to increase the measurement accuracy,

Figure 1 shows the structural electrical circuit of the proposed device; Fig. 2 shows the stress plots showing his work.

A device for measuring the amplitude-frequency characteristics of quadrupoles contains a modulating voltage block 1, indicator 2, oscillating frequency generator 3, 4 clock pulse generator, memory block 5, binary counter 6, frequency mark unit 7, electronic display 8, first 9 and second 10 electronic keys, the first 11 and second 12 amplitude selectors, delay line 13, the third electronic key 14, the amplifier 15, the decoder 16 and the quadripole under study 17.

The device works as follows.

The modulating voltage unit 1 generates signals that simultaneously produce a deflection of the beam of the inductor 2 horizontally, thereby creating a sweep / cloud in frequency with the same time

The key 14 is opened and this pulse is fed from line 13 to the amplifier 15. And due to the fact that the bandwidth of the MFR 17 is usually measured at a level of 0.707 from the max. Frequency response, coefficient, gain of the amplifier is equal to 0.707. A pulse with an amplitude of 0.707 from the maximum value of the frequency response is fed to block 5, then to the second input of the AC 12, to the first input of which a sequence of pulses is fed from the key 9. This completes the first cycle of operation, characterized by a change in the frequency of the modulating oscillation from f to the second cycle - when changing from f, to

 The cop

f.MwH. 1 il.

scale, and control the frequency tuning of the generator 3 of the frequency, the generator operation 4 clock

pulses and binary counter 6,, t

From the second output of the oscillator J oscillator frequency (FIG. 2a), the frequency modulated signal is applied to the quadrupole 17 under investigation. When passing through the latter, due to

whether the transmission coefficient is frequency dependent; amplitude modulated (FIG. 2d); the first generator output

3 oscillating frequencies are connected to the input of a block of 7 frequency marks. The marks are formed by mixing the signals of the reference and swing frequencies. The signal from the block 7 frequency labels

is fed into the channel of the vertical deflection amplifier and is observed on the display of the indicator 2 in the form of bursts marking the frequency.

From the output of the studied quadrupole 17, the signal simultaneously enters the information input of the first electronic key 9 and the third input of the indicator 2, where the visual display of the studied

the amplitude-frequency characteristic of the investigated circuit of the rechpolus 17; The output of the first electronic key 9 is a sequence of clock pulses received from 1 4 x generator of 4 clock pulses (Fig. 26 amplitude modulated in amplitude from the output of the terminal 17,

This pulse sequence is fed simultaneously to the first input of the second amplitude selector 12, to the information input of the second electronic key 10, to the first input of the first amplitude selector 11 and through the delay line 13 to the second input of the first amplitude selector 11 and information input of the third electronic key 14. Constant the time of the delay line 13 is equal to the period of the following clock pulses, which ensures that the first and second inputs of the first amplitude selector 11 simultaneously arrive at the first and second inputs Next: his and previous pulses from the pulse sequence. In the first amplitude selector 11, the amplitudes of the subsequent and previous pulses are compared. As soon as the amplitude of the subsequent pulse becomes less than the amplitude of the threshold, the first amplitude selector 11 will give the decisive pulse to the control input of the third electronic key 14.

Thus, the first amplitude selector 11 selects the pulse with the maximum amplitude from the entire pulse sequence. In Fig. 2b, this pulse is designated as N, and the amplitude of this pulse corresponds to the maximum value of the amplitude-frequency characteristic of the quadripole 17 under investigation. When the first amplitude selector 11 is triggered, the third electronic key 14 is opened and the pulse with the maximum amplitude comes from the delay 13 output to the amplifier 15. Due to the fact that the bandwidth of the quadrupole 17 under study is usually measured at the level of 0.707 of the maximum value of the amplitude-frequency characteristic, Sileni amplifier 15 is selected to be 0.707. From the output of the amplifier 15, a pulse with an amplitude equal to 0.707 of the maximum value of the amplitude-frequency characteristic of the quadrupole 17 under study is shown to memory block 5, in which it is stored. From memory block 5, a given pulse is applied to the second

A second amplitude selector-12 input, the first input of which supplies a sequence of pulses from the output of the first electronic key 9. This completes the first cycle of the device, indicated in Fig. 2a with a time interval from O to T and characterized by a change in the frequency of the modulating oscillation from

- min.

and f

ADIX

f5

0

five

0

five

0

five

0

five

The second cycle of operation of the device is indicated by the interval from T to T, (Fig. 2a), the frequency of the modulating oscillation varies from f to f. In this period, in the second amplitude selector 12, the amplitudes of the pulses arriving at its inputs are compared. When a second amplitude selector 12 arrives at the first input, the amplitude of which is equal to 0.707 of the maximum amplitude-frequency characteristic value of the quadrupole 17 under study (in FIG. 2g, this pulse is designated as (S)), the second amplitude selector 12 outputs a pulse to the second input of the second The electronic key 10, which opens, and the binary counter 6 starts counting the pulses coming from the output of the first electronic key 9 through the second electronic key 10 to the information input. The counting of pulses occurs until the next pulse with an amplitude equal to 0.707 from the maximum one arrives at the first input of the second amplitude selector 11 from the output of the first electronic key 9. In this case, the second amplitude selector 12 re-triggers and produces a pulse, which locks the second 1U electron key. Binary counter 6 stops its operation.

The number of pulses counted by the binary counter 6 is equal to t, which corresponds to the bandwidth of the quadrupole under study 17. The decoder 16 converts the measurement result to be displayed on the electronic display 8. With the arrival of a new pulse, a new measurement cycle begins. The tuning rate of the oscillating frequency generator 3 depends on the measurement range of the modulating signal j f f. ,, LpOK &

fd ,, „AND FROM the measurement period T. The rate of adjustment is calculated by the formula

V,

PER

 Z y i1ТГ

The period of the clock pulses generated by the 4 clock pulse generator must be chosen depending on the tuning speed of the 3 oscillating frequency generator. This dependence is determined by the formula

T - -

V

PER

those. by increasing the tuning rate, it is necessary to reduce the period of the clock pulses. The choice of optimal values of V; gp and T is carried out for each specific case separately.

Claims (1)

Invention Formula A device for measuring the amplitude-frequency characteristics of a quadrupole, containing a oscillating frequency generator, the first output of which is the input of the quadrupole under investigation, a series of modulating voltages connected in series and an indicator, the second input of which is the output of the quadrupole under investigation, a block of frequency labels, the output of which is connected to the third the indicator input, clock pulse generator, the first, second and third electronic switches, amplifier, serially connected binary account The control input of which is connected to the second output. 908106 module of modulating voltage, decoder and electronic scoreboard, the second output of the module of modulating voltage. connected to the input of the generator of a frequency-sensitive frequency, (it is so that, in order to measure the accuracy of the measurement, the first and second amplitude selectors are introduced, the first inputs of which are connected to the output of the first electronic key, the control and information inputs of which connected respectively to the output of the clock pulse generator d NS the output of the studied quadrupole, the delay line, the input and output of which are connected respectively to the output of the first electronic key, the second input of the first amplitude selector and the information input of the third key, the control input and output of which are connected respectively to the output of the first amplitude selector and input usi25 the memory unit whose input and output are connected respectively to the output of the amplifier and the second input of the second amplitude selector, the output of which is connected to the control input of the second The electronic key, whose information input and output are connected respectively to the output of the first electronic key and the binary counter information input, the second output of the modulating voltage block is connected to the input of the clock generator, the second output of the oscillating frequency generator is connected to the input of the frequency tag block. 35 FIG. 2