SU1566300A1 - Apparatus for measuring impedances - Google Patents

Abstract

The invention relates to electrical measurements and can be used to measure the impedance of bipolar and quadripolar components, in particular, when tuning cascades of radio transmitting devices. The goal is to improve the accuracy of measurements in a wide range of frequencies. For this, a random access memory 7, a persistent storage device 9 and a correlator 8 are inserted into the device. The device also includes a measuring line 1 with N field distribution sensors 2 arranged along it, a field generator 3 signals, a program-controlled switch 5, an analog-digital a converter 6; and a processing and software control unit 10 comprising a comparator, a decoder, and a clock generator. 1 hp ff, 2 ill.

Description

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The invention relates to electro-radio measurements and can be used to measure the impedance of bipolar and four-pole components, including active, in a wide frequency band of meter and decameter wavelengths, in particular when tuning radio transmitters.

The purpose of the invention is to improve the accuracy of measurements in a wide frequency range.

Figure 1 shows a block diagram of a device for measuring impedances; Fig. 2 is a block diagram of the processing and program control unit.

The device contains a measuring line 1 with N field distribution sensors located in it in line 2, to which a signal generator 3 is connected on one side, and a load 4 being investigated on the other, a program-controlled switch 5 are sequentially connected to the outputs of the field distribution sensors 2, analog-to-digital converter (ADC) 6, random access memory (RAM) 7 and correlator 8, to the second input of which the first output of the permanent storage device (ROM) 9 is connected, the output of the correlator 8 is connected to the first input The unit of processing and software control unit 10, the first, third and fourth outputs of which are respectively connected to the control input of the program-controlled switch 5, the second input of RAM 7 and the input of the ROM 9, is connected to the second output of the control and program processing unit 10 the switch 11, the second input of which is connected to the second output of the ROM 9, and the output of the controlled switch 11 is connected to the input of the unit

12 withdrawal of information.

The processing and software control unit 10 comprises a comparator 13, a decoder 14 and a clock pulse generator 15 (GTI), the output of the comparator 13 being connected to the output of the core. relay 8, the first input of the comparator

13 is connected to the first input of the controlled switch 11, the second output of the comparator 13 is connected to the first control input of the decoder 14, the clock pulse generator 15 is connected to the second input of the decoder 14,

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the first, second and third outputs of which are respectively connected to the second input of the RAM 7, the input of the ROM 9 and the control input of the software-controlled switch 5.

The principle of operation of the device is to compare the voltage distribution in the measuring line with an unknown load with the voltage distribution in the same line when the reference loads are connected by calculating the correlation function.

The device works as follows.

In the interaction of the propagating from the generator 3 signals and the reflected load from the test 4 electromagnetic waves in the measuring line, a certain voltage distribution is defined, described by the following expression:

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b (x) U,

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where u (x) u + j

R x voltage distribution along the length of the measuring line;

voltage on load 4 measuring line; constant distribution;

active load resistance component; reactive load resistance component. The voltage distribution established in the measuring line 1 is taken at points x. sensors 2 distribution floor. Here x. - coordinate of the 1st sensor.

A software-controlled switch 5 sequentially connects the field distribution sensors 2 to the input of the A / D converter 6, where analog information about the distribution value in the U (xj) line is digitized U (x-) and recorded in RAM 7. The switching of the 1st sensor and write to RAM occurs synchronously according to the control signal generated by the processing and program control unit 10.

Preliminarily, in the ROM 9, for possible values of Zm R m + jXH parameters of a specific measuring line 1 and taking into account the characteristics of the sensors for the required frequency range, the measurement of the value of the barometric voltage distribution is entered

1 FL (x, Z and) in points

I

Wherein

j G 1, MJ, where j is the number of the reference load, M is the number of values Z ,,, zapip

It can be noted that in most practical situations it is possible to specify the boundaries in which the values of Z change with the required probability, and thereby limit the value of M within reasonable limits.

The values of U (x,) and U (x, Z) are sent to the correlator 8 by the sampling commands generated by the processing and software control unit 10, and the j-th load resistance value is fed to the controlled switch 11 from the ROM 9 at the same time.

The correlator 8 calculates the correlation function of the test and reference stress distribution in the measuring line in accordance with the expression

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this is U U (x) U, r (x.

Z). (2

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The calculated value of the correlation function is fed to the processing and program control unit 10.

The value of the calculated correlation function is fed to the input of the comparator 13 and is compared with the threshold value. If the value of the calculated correlation function is more or early than the reference value, then the comparator 13 generates a command to transfer the j-ro load value from the controlled switch 11 to the information output unit 12 and reset the decoder 14. Otherwise, from the comparator to the decoder 14 a command is received to continue iterating the values of the reference load resistances and the controlled switch 11 from the ROM 9 enters (jtl) -e value of the load resistance, and the process of searching for load resistance is measured itelnoy line extends.

From the output of the GTI 15 to the decoder 14, a pulse sequence is received, the first n pulses being used by the decoder 14 to generate synchronous control commands for switching the sensors 2 by the program-controlled switch 5 and writing information into the corresponding RAM cells 7. Starting from (n + 1) -th momentum

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The decoder 14 generates sampling commands for reading the values U (x () and U JT (x., ZH.) from RAM 7 and ROM 9, respectively.

The water information block 12 serves to indicate the obtained value of the load resistance.

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Formulas

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Claims (2)

1. A device for measuring impedances containing a signal generator, to the output of which a measuring line is connected with field distribution sensors located along it, connected through a program-controlled switch to an analog-to-digital converter, a processing and program control unit whose first output connected to the input of a software-controlled switch, and the second through a controlled switch connected to the input of the information output device, while the output of the measuring line is an output for connecting the test load, which is due to the fact that, in order to improve measurement accuracy in a wide frequency range, a random access memory, a permanent memory and a correlator are inserted into the device, the first input of the random access memory is connected to the output A / D converter, the second input is to the third output of the processing and program control unit, the output of the random access memory is connected to the first input of the correlator, the second input to torogo connected to the first output of the constant memory, the correlator output is coupled to the input of the processing unit and software controlling the second controllable input switch is connected to the second output of the constant n; storage device whose input is connected to the fourth output of the processing and program control unit. 2. Device pop. 1, characterized in that the processing and software control unit comprises a comparator, the first output of which is connected to one of the inputs of the decoder, the other input of which is connected to the output of the clock generator pulses, while the comparator input is the input of the block, the second comparator output is the first HSS MaSffJJ Ha5 Hal ± go -t ± l V The stroke of the block, the outputs of the decoder, respectively, are the second, third, and fourth outputs of the block.