SU1166015A1 - Device for measuring parameters of microwave elements - Google Patents

Abstract

1. A DEVICE FOR MEASURING THE PARAMETERS OF THE MICROWAVE ELEMENTS, containing a microwave generator, successively connected to a segment of the microwave path with a measuring probe connected to the amplitude detector, and a controlled phase shifter, the output of which is an input for connecting the microwave element under study, and controlling the input is connected to the output of the control unit, which differs from L in that, in order to increase accuracy, between the output of the microwave generator and the input of the segment of the microwave path with the measuring probe, a circulator is turned on, the third arm of which is loaded for a matched load, the first peak detector and the first adder, the output of which is the first output of the device, are sequentially connected to the output of the amplitude detector, between the output of the amplitude detector and the input of the control unit in series with a differential amplifier, the second input of which is connected to the output of the first peak detector, the second peak a detector whose output is the second output of the device, a second adder, the second input of which is connected to the output of the first peak detector, and the output is with the second input of the first adder, a comparator, the second input of which is connected to the output of the amplitude detector, and a trigger, the output of which is the third output of the device, is connected to the control output of the PIR tracking unit, the control input of which is connected to the output of the trigger, and the output is an even vertical output device, 2. The device according to claim 1, characterized in that. The tracking unit consists of a serially connected first operational amplifier, whose input is the input of the tracking unit, an analog switch that controls the input Od of which is the control input of the tracking unit, the source O repeater with a storage capacitor at the input, and a second operational amplifier, the output of which is the output of the tracking-storage unit. 3. The device according to claim 1, distinguished by the fact that the phasing unit contains a series-connected constant two-pole voltage source, a two-channel switch, the control input of which is the input of the control unit, and a linear voltage generator, whose output is The output of the control unit.

Description

The invention relates to a measurement technique and can be used to measure the reflection coefficient, standing wave ratio and the impedance of microwave elements.

The purpose of the invention is to improve accuracy.

FIG. 1 shows a structural electrical circuit of a device for measuring parameters of microwave elements; FIG. 2 is a structural electrical diagram of the tracking unit.

A device for measuring the parameters of microwave elements contains a microwave generator 1, a circulator 2 with a matched load 3 in the third arm, segment A of the microwave path with a measuring probe 5, controllable phase shifter 6, the microwave element 7 under study, amplitude detector 8, differential amplifier 9, first and second peak detectors 10 and 11, first and second adders 12 and 13, comparator 14, trigger 15, tracking block 16, consisting of first and second operational amplifiers 17 and 18, analog switch 19 and source follower 20, control block 21, comp discharged from source 22 constant dvuhpol molecular voltage, switch 23, oscillator 24 linearly varied gatsegos voltage and .bloking generator 25, analog-to-digital converter 26, a microprocessor 27, a digital display 28, a storage capacitor 29.

The device for measuring the parameters of the microwave elements operates as follows.

High-frequency oscillations from the microwave generator 1 are received through a compass: a torus 2 into a segment 4 of the microwave path, pass through a controlled phase shifter 6 and reflector from the microwave element 7. The reflected high-frequency oscillations pass through the controlled phase shifter 6 (for example, in the form of nonreciprocal ferrite phase shifter), changing its phase by the value determined by the voltage supplied from control unit 21 to control input of controlled phase shifter 6, section 4 of the microwave path, then through the circulator 2 reflected high-frequency the vibrations enter the matched load where they are absorbed.

In the section of the microwave path, as a result of the interference of the incident and reflected waves, a standing wave occurs, and at the connection point of the measuring probe 5, the phase of the reflected wave is shifted relatively by

four

0)

 - phase of the reflection coefficient of the studied microwave element 7; dH is the phase shift introduced by the controlled phase shifter 6 (phase shift corresponding to the distance from the measuring probe 5 to the microwave element 7 and back).

In this case, the voltage of the detector detector is

, -, .., (.. W

where E is the intensity of the falling

waves

G is the modulus of the reflection coefficient of the microwave element 7 under study.

After detecting the voltage and the amplitude detector 8 operating in a linear mode, the voltage at its output is determined by the expression

Ur, bl | .r4rcos (f- / l - X,), O)

where K is the coefficient of transmission of the amplitude detector 8. The linear mode of operation of the detector 8 is preferable for the following reasons::

The device can be used in real equipment, the output power of the transmitters from which can reach a considerable amount (tens to hundreds of kilowatts), while it is not possible to ensure the operation of the amplitude detector 8 in the quadratic mode. In order to determine the values of J and H, while excluding the unknown value EIJ, it is necessary to have a system of two equations, whereas when the amplitude detector 8 operates in a quadratic mode, it is necessary to have a system of at least three equations. The output voltage of the amplitude detector of detector 8 is maximum U, max is minimal At those points in time when the phase change made by the controlled phase shifter 6 is equal to and Smoks tMHH em "cc tmin l / i, jr-lL X Ag о From the system of two Equations (4) determine the modulus of the reflection coefficient r and its phase V, determined at a time; when the voltage at the output of the amplitude detector 8 is equal to and, ьми. G.: | x ... () -, (5) 6 max l 2. my- -f-M-. (Aj The process of determining the modulus and phase of the reflection coefficient of the studied microwave element 7 is as follows. The blocking generator 25 operates either in self-oscillatory or in standby modes, which is determined by the mode of operation of the microwave generator 1. A pulse from the output of the blocking generator 25 the flip-flop 15 is tripped. A single output state from which is fed to the control is looking for the input of the switch 23. The switch 23 connects to the input of the generator 24 a linearly varying voltage output + E of the source 22 of a constant two-pole voltage. The automatically increasing voltage from the output of reHepaTop 24 linearly varying voltage is supplied to the control input of the controlled phase shifter 6, which changes the phase reflected from the microwave element 7 being investigated and the voltage at the amplitude of the amplitude change. detector 8, This voltage simultaneously arrives at the input of the first peak detector tO, nepBbrii input of the differential amplifier 9 and the first input of the comparator 14. The first peak detector 10 detects and remembers the voltage of the MFCC that goes to the second input differential amplifier 9, where the difference is not the maximum maximum MCKKC U by the current U signals from the amplitude detector 8. The maximum difference U AIOKC -Uj is allocated and stored by the second peak detector 11. The output voltage of the first peak detector 10 and U ,, -and / ,, "from the output of the second peak detector 11 is fed to the second adder t3, where the second is subtracted from the second and a voltage is obtained that is supplied to the second input of the comparator 14, where it is compared with the current voltage Ug supplied to his first entrance is from :: the output of the amplitude detector 8. At the moment of their equality, the comparator 14 changes its state at the output, thereby tipping the trigger 15 into the zero state at the output, which goes to the switch 23, the switch 23 produces a linear voltage of the generator 24 The output is -E source 22 of a constant two-pole voltage. The voltage at the output of the generator 24 linearly varying voltage will begin to linearly decrease, thereby changing the phase of the reflected wave in the other direction until reaching the next minimum standing wave in section 4 of the microwave path at the location of the measuring probe 5. The process of tuning from minimum to minimum and back will be repeated as long as there is an electromagnetic wave in section 4 of the microwave path. In the case of pulsed operation of the microwave generator 1, launching the device into the measurement mode is performed by the modulating pulse of the microwave generator 1 by starting the blocking generator 25. Voltage ,,. From the output of the first peak detector 10 and the output of the second adder 13, they are fed into the inputs of the first adder li, which they are in and out and ten times the output of the first adder 12 goes to the first turn of the analog-digital converter 26. The voltage (mine the output of the second peak detector 1 is fed to the second input of the analog-to-FLULL converter 26. The output of the trigger pulse 15, whose duration is proportional to the standing wave in section 4 of the SVChrakt, is fed to the third input of the analog-digital converter 26. The output voltage The generator 24 of the linearly varying voltage is fed to the input of the block 16. At the time j, when the measuring probe 15 detects the first minimum of the standing wave from the microwave element 7 being investigated, the trigger 15 is tilted from zero to one at the output, which triggers on the control the input unit 16 to the storage mode of the output voltage Ui of the generator 2A linearly varying voltage is directly proportional to the phase shift introduced by the controlled phase shifter 6, passed to the fourth input of the analog-digital converter 26. V analog-to-digital converter 26, the input voltages and the pulse duration of the trigger 15 are converted into a Dafra code during a single pulse from the output of the trigger 15. The analog-digital converter 26 is reset to the zero state during a zero output pulse of the trigger 15. Converted analog digital converter 26 to digital code of input voltage values and pulse duration trigger 15 enters the corresponding inputs of the microprocessor 27, which calculates the module G and phase H to by reflecting the intrinsic reflectance coefficient of the controlled phase shifter 6. Using the calculated values of the module and phase, the reflection coefficient of the microprocessor 27 calculates the values of the standing wave coefficient Kj.g, the active and reactive components of the input the resistance of the investigated microwave element 7 according to the respective values of the modulus and phase of the reflection coefficient, standing wave coefficient, active and reactive components of the input resistance of the investigated microwave element 7 are displayed on digital th display unit 28. The tracking -retention 16 operates as follows. When the analog switch 19 is closed, which corresponds to the zero state on its control to the input, the voltage on the storage capacitor 29 monitors the input voltage and is exactly equal at each time instant. When a single impulse from the trigger 15 arrives at the control input of the analog switch 19, it softens and the voltage at the tracking-tracking unit 16 is equal to the voltage stored on the accumulator capacitor 29 at the time preceding the opening of the analog switch 19. The voltage leakage on the accumulator the capacitor 29 is extremely small, since its load is a source follower 20 with an insulated gate, does not consume current from the input circuit, which is a storage capacitor 29. The storage tracking unit 16 injures value of the input voltage equal to voltage generator 29 with linearly varying voltage at the time point when the measuring probe 5 is at least the first standing wave. This voltage from the output of the tracking unit 16 is fed to the fourth input of the analog-digital converter 26.

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Claims (3)

1. DEVICE FOR MEASURING THE PARAMETERS OF MICROWAVE ELEMENTS, comprising a microwave generator, connected in series with a segment of the microwave path with a measuring probe connected to an amplitude detector, and a controlled phase shifter, the output of which is an input for connecting the studied microwave element, and the control input is connected to an output of the control unit, characterized in that, in order to increase accuracy, a circulator is connected between the output of the microwave generator and the input of the segment of the microwave path with the measuring probe, the third arm of which is loaded on the combined load, the first peak detector and the first adder, the output of which is the first output of the device, are sequentially connected to the output of the amplitude detector, between the output of the amplitude detector and the input of the control unit, a differential amplifier is sequentially switched on, the second input of which is connected to the output of the first peak detector, the second peak detector, the output of which is the second output of the device, the second adder, the second input of which is connected to the output of the first peak detector, and the output to the second course of the first adder, a comparator, a second input connected to the output of the amplitude detector, and a trigger, the output of which is a third output device is connected to the control output of the tracking-storage unit, a control input coupled to an output flip-flop, and the output is the fourth output ustroystav. 2. The device according to π. 1, characterized in that. the tracking-storage unit consists of a series-connected first operational q amplifier, the input of which is the input of the tracking-storage unit, an analog key, the control input of which is the control input of the tracking-storage unit, a source follower with a storage capacitor at the input, and the second operational amplifier, the output of which is. It is output by the tracking-storage unit. 3. The device pop. 1, which is molded in that the control unit comprises a DC bipolar voltage source connected in series, a two-channel switch, the control input of which is the input of the control unit, and a ramp generator, the output of which is the output of the control unit. I