SU1483414A1 - Device for calibration of selective measuring instruments - Google Patents

Abstract

This invention relates to a measurement technique. The purpose of the invention is to improve accuracy. The pulse generator 1 generates a signal like a square wave. At the output of the logic element 6, a sequence of rectangular, optimally distributed pulses in time is formed, in accordance with the information stored in memory block 3. The control signals to block 3 and multiplexer 4 from switch block 5 expand the number of variants of the pulse sequences at the output of the device. The amplitude of the harmonics of the output signal is calculated from the ratio of the amplitude of the pulses of the pulse generator 1, the counting coefficient of the counter 2 and the number of pulses in the period of the output signal of the devices. The goal is achieved by reducing the levels of the side spectral components in the spectrum of the output signal of the device. 2 Il.

Description

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The invention relates to a radio metering technique and can be used to calibrate the amplitude scales of selective measuring instruments, such as selective voltmeters, network analyzers, measuring receivers, spectrum analyzers, etc.

The purpose of the invention is to improve the accuracy of calibration of the amplitude scales of selective measuring instruments by reducing the levels of side spectral components in the spectrum of the output signal of the device for calibration.

FIG. 1 is a block diagram of a device for calibrating selective measuring instruments; in fig. 2 - voltage plots showing the operation of the proposed device.

A device for calibrating selective measuring instruments comprises a pulse generator 1, a counter 2, a memory block 3, a multiplexer 4, a switching block 5, a logical element AND 6.

The output of generator 1 is connected to the first input of logic element 6 and the input of counter 2. The outputs of counter 2 are connected to the first group of control inputs of memory block 3, the outputs of which are connected to the corresponding information inputs of multiplexer 4. The first group of outputs of switching block 5 is connected to the second a group of control inputs of memory block 3, and the second group — with control inputs of a multiplexer 4. The output of multiplexer 4 is connected to the second input of the AND 6 logic element, the output of which is the output of the device.

The proposed device works as follows.

In memory block 3, the sequence of "O and" 1 is arranged in such an order as to provide a signal at the output of the device with a predetermined distribution of pulses in time.

The generator 1 produces pulses of type square wave, having constant temporal characteristics (Fig. 2a), which are fed to the inputs of logical AND 6 and counter 2 with the counting coefficient P (P is an integer). When a pulse 2 is applied to the input of the counter 2, the counter at the information outputs generates signals by means of which sequential polling of the addresses of memory block 3 takes place. In this case, at each output of the memory block 3, its own sequence of rectangular pulses is formed in accordance with the burning code (Fig. 2a).

The control signals from the switching unit 5 expand the number of variants of the pulse sequences at the outputs of the memory unit 3.

The second group of control signals, represented in binary code, from the outputs of the switching unit 5 is fed to the control inputs of the multiplexer 4. When

In multiplexer 4, in accordance with the control code, the required information input of the type 4 multiplexer is connected to its output.

0

five

0

The inputs of the logical element I are set to the pulses of generator 1 (fig. Pulses of multiplexer 4 (fig. 26). The logical element AND 6 operates in such a way that it either passes the pulses of generator 1 (at the output of the multiplexer is “I”) or does not pass them (at the output of the multiplexer ()). At the output of the calibration device, a sequence of rectangular, optimally distributed pulses in time is formed, in accordance with the information stored in memory block 3 (flash 2c).

The output signal of the device is riod G, which without loss

ANY t 1/7 - NUMBER.

de T is equal to

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all on the pp;; K p // ti iO // t

C: 1

where p is the parameter defining the period

output signal: 1 // and - pulse frequency

generator.

The output spectrum consists of harmonics that are multiples of the frequency of the first gamonic of this signal /, defined as

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(2)

Harmonic amplitude at frequency / g

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.four,,

at Ј

) is determined

mr

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five

0

five

where Ј is the amplitude of the pulses.

When calibrating the amplitude scales of the instruments using the proposed device from the output signal of a stroyspe, using a filter of a selective instrument. The harmonics of the frequency i1 are identified on the instrument scale. therefore, those t / ps get a p d value on an amplitude scale. Then, according to the dependence of the | 3 amplitude of the harmonic, oi ratios, the calculated spacing is determined, the amplitude of the harmonic and otopeak-cho are calculated and experimentally:; the most significant differences determine the scale of the scale. . E. Calibrate it.

Experimental investigators: :: v.: .- the device under consideration is shown, which is also a calibrated variation of harmonic G at a frequency;, cocia: 5. in rank less than ± 0.5 dB in the range up to -U as with the known device.

Into the filter band of a measuring instrument when harmonics are extracted by it ;; At the frequency and signal of the device, the same as in the prototype, the preceding h are entered; the spectrum; The main components of this signal, the posture are gyr / .o1 I K KS, OYR (n ОНЬп ч

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FIG.

Claims (1)

Claim A device for calibrating selective measuring instruments, comprising a pulse generator, a switching unit, a logic element I. ... and its output is the output of the device, which is characterized by the fact that, in order to increase calibration accuracy, an additional memory unit, multiplexer and counter are inserted into it; to the first group of control inputs of the memory block, outputs. For example, 10 are connected to the corresponding inf.input inputs of the multiplexer, the output of which is connected to the second input of the logic element I. Moreover, the output group of the switching block is connected: with the second group of control inputs of the block '- ³ memories, and the second group of outputs of the switching block connected to the control inputs of the multiplexer.