SU1437803A1 - Device for measuring attenuation of microwave four-pole networks - Google Patents

Abstract

This invention relates to a microwave measurement technique. The purpose of the invention is to increase the measurement accuracy and optimize the device. The device contains microwave rr-1, control unit (CU) 2 frequency tuning, power divider 3, frequency shift block 4, rc 5 pi1g.shaped voltage, switches 6 and 9, we investigate microwave four - the pole 7, the reference attenuator 8, the mixer 10, the intermediate frequency 11, the detector 12, the indicator 13, the delay unit (BZ) 14 and the frequency shift controller 15. When the quadrupole 7 is turned on in the signal path on the indicator 13, the amplitude-frequency attenuation frequency of this quadrupole 7 is observed. After switching the switches 6 and 9 on the indicator 13, the amplitude-frequency attenuation attenuator 8 is displayed. Changing the attenuation value of the attenuator 8, its x-ku to touch with interest is the x-ki point of the four-port circuit 7. The magnitude of the measured attenuation is measured on the scale of the attenuator 8. The goal is achieved by the introduction of BU 2, KB 14 and controller 15. 1il. (L

Description

The invention relates to a technique for measuring on microwave and is intended to measure large attenuation of quadrupoles,

The purpose of the invention is to improve., - the accuracy of measurements and simplify the device.

The drawing shows the electric

frequency controlled generator 5 sawtooth voltage. Then, through the delay unit 14 with the delay time CQ, the signal is fed to the input of the first switch 6, which switches synchronously with the second switch 9. With the help of these switches, either

A block diagram of the device for JQ investigated microwave four-port 7

measurements of attenuation of the SACh-chesh.kh1 OUSNIKOVO

A device for measuring the attenuation of the RF quadrupole contains, microwave generator 1, frequency tuning control unit 2, divider 3 power, frequency frequency offset unit 4, pipiform voltage generator 5, first switch 5 of microwave microwave quadruple pad 7, reference voltage .20

: tenuator 8 ,, second switch 9, mixer 10, intermediate frequency feller 1 j, detector 12, indicator 13, delay block 14 and. frequency shift controller 15.

A device for measuring the attenuation of the microwave circuit of the rechpoles works as follows.

The frequency of the microwave generator 1 is tuned according to the sawtooth law in the given frequency range 4F by the signal

. from the output of block 2 control frequency tuning

or an adjustable local attenuator 8, From the output of the second switch, the 9 signal is fed to the input of the mixer 10. Due to the shift of 15th frequency and the delay of the signal as it passes through the signal path at the signal input of the 10h mixer, FJ, signal and shift its phases are determined by the following

, -b. (t-g; -fJ- f V, (t +, :),

eating

(4) (5)

25 where the frequency of the pilot saw-shaped voltage; Sf. signal delay time

signal path without f. ;

Od - the delay time in block 1 delay, which is chosen from the condition

LR

F, About t T,

(one)

where Ft, is the initial frequency of the given

T band - frequency tuning period

in the specified range The signal from the output of the microwave generator 1 through the second output of the power divider 3 is fed to the heterodyne input of the mixer 10 "Due to the back-trip when the signal propagates along the heterodyne path, the signal at the heterodyne input of the mixer 10 is phase-shifted; tote. Fp signal frequency and phase shift q; on the heterodyne input of the mixer 10 are determined by the expressions;

F F,

 ii (t-H) k. . g

.Where

(2)

Cj; 21 F C,. . (3)

. Sf.- signal delay time in the heterodyne pathway, with i l / J- / TJ. about

P

  t., through the first output of the divider 3, the signal is fed to the input of the block 4 shift

or an adjustable local attenuator 8. From the output of the second switch 9, the signal is fed to the input of the mixer 10. Due to the frequency shift and the signal delay when it propagates through the signal path at the signal input of the mixer 10, the frequency FJ, the signal and the phase shift c / are determined by the following phages:

F, -b. (t-g; -fJ- f V, (t +, :),

eating

(4) (5)

where is the frequency of the pilot sawtooth; Sf. signal delay time

signal path excluding f. ;

Od is the delay time in block 14 of the delay, which selects-- s from the condition

about 7

Th)

24F

(6)

where (1 is the bandwidth of the intermediate frequency bandpass filter 11.

With this +.

At the output of the mixer 10, the signal has a frequency

& F

) (7)

The amplitude of this signal is determined by the attenuation of the microwave path. Due to the incomplete suppression of the carrier frequency in block 4 of the frequency shift, the amplitude of the output signal of the mixer 10 depends on the phase difference of the c-signals at the signal and heterodd1 inputs of the mixer. When tuning the frequency / 2 irF (.). With uch-;. volume (1)

2GR, “(1,

2AF

() - fft (8)

The output signal is amplitude modulated with a frequency

24F

 fcx

()

The parasitic amplitude modulation causes the spectrum of the output signal of the mixer 10, in addition to the component with frequency, p, to appear at frequencies f p +

i fffoK

With the equation (6) inequalities I. 7 / T, f

and (9) as well

(ten)

f approx.

Thus, the signals with frequency will pass through the band-pass filter with a pass-band P amplifier 11 of the intermediate frequency with great attenuation.

If the intermediate frequency amplifier filter is set to a frequency other than ffip, then the automatic frequency tuning system of the amplifier with the 11th frequency frequency provides a control signal to the frequency shift controller 15.

The signal is then fed through a detector 12 to the input of an indicator 13, synchronized by a signal from the output of block 2..

Thus, when the studied quadrupole 7 is included in the signal path on the indicator 13, the amplitude-frequency characteristic of the attenuation of this four-pole is observed. After switching the switches 6 and 9 on the indicator 13, the amplitude-frequency characteristic of the attenuation of the reference attenuator 8 is displayed. By changing the attenuation value of the reference attenuator 8, the characteristic of the attenuator 8 is brought to the point of interest of the quadripole 7 with a point of interest.

the measured attenuated is measured on the scale of the reference attribute of the nu- tator 8.

5 formulas and inventions

.

ten

15

A device for measuring the attenuation of a microwave quadrupole containing a series-connected microwave generator, a power divider and a frequency shift unit, the control input of which is connected to the output of a sawtooth generator, serially connected first switch, reference attenuator, second switch, mixer, intermediate frequency amplifier , a detector and an indicator, the second output of the first switch being the output for connecting the input of the tested four-port network, and the second input of the second ereklyuchatel is input for coupling the test output quadripole, characterized in that, in order izmerensh A rise scheni accuracy and simplify the apparatus, it is further administered a control unit of frequency adjustment, pervm whose output is connected to the control input of the microwave kschim genera20

25

thirty

the second output is connected to the second input of the indicator, the delay unit is connected between the output of the frequency shift unit and the input of the first switch, the frequency shift controller, whose input is connected to the second output of the intermediate frequency amplifier, and the output is connected to the input of the sawtooth voltage generator the heterodyne input of the mixer is directly connected to the second output of the power splitter.

Claims (1)

5 claims A device for measuring attenuation of a microwave four-port network, comprising a series-connected microwave 10 generator, a power divider and a frequency shift unit, the control input of which is connected to the output of a sawtooth generator, the first switch 15 connected in series, a reference attenuator, a second switch, a mixer, an intermediate frequency amplifier, a detector and an indicator, and the second output of the first switch is an output for connecting the input of the four-terminal under study, and the second input of the second reklyuchatelya is input to connect the output of the test quadripole, characterized in that, in order to improve measuring accuracy and simplify the device, it is further introduced frequency hopping control unit, a first output connected to the control input of the microwave generator, and a second output connected to a ₄ second indicator input, delay unit * connected between the output of the frequency shift unit and the input of the first switch, the frequency shift controller, the input of which is connected to the second output of the amplifier second frequency, and an output coupled to an input of the sawtooth generator, wherein the hetero one input of the mixer is directly connected to the second output of the power divider.