SU1166007A1 - Quasiperiodic signal analyser - Google Patents

Abstract

KVAZIPERYODICHESKIH SIGNAL ANALYZER, codepzhaITstdi n parallel channels, each of which consists of series-connected smart CITEL regulated integrator and registrar, and count pulse generator i.generator Walsh functions pervn terminals connected to inputs of the multipliers of all channels, the second inputs of which are combined and connected to the i output of the inverter, and third combined inputs connected simultaneously to the input of the inverter and the analyzer input, characterized in that, in order to increase the accuracy measurements, serially connected counter-divider, memory block and comparison circuit, as well as a counter, a generator of control signals and a digital-to-analog converter, whose inputs are connected to the corresponding outputs of the memory block and the output connected to the first control inputs of adjustable integrators all channels, while the second inputs of the circuit are compared-. They are connected to the outputs of the counter, the first input of which is connected to the output of the generator of counting pulses and simultaneously to the first input of the counter-delntel, the second input of which is connected to the clock input and connected to the second input of the counter, which controls the input of the memory block and the first input control signal generator, the output of the comparison circuit is connected simultaneously to the input of the Walsh function generator, the third input of the counter and the second input of the control signal generator, one output of which is connected to the second control input The waters of the adjustable integrators of all channels, and the other with the control inputs of the recorders of these channels.

Description

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The invention relates to information and measurement technology and can be used to analyze a quasi-periodic signal by its spectral components.

A digital spectrum analyzer is known, comprising a clock pulse generator, a Walsh function generator, a delay element, a logic unit of ambiguity, reversible counters, a memory cell and a voltage-to-voltage converter TI 3.

However, this device has a large error in determining the decomposition coefficients in the Walsh series for frequencies above 1 kHz.

The closest in technical essence to the invention is a periodic signal analyzer comprising a series-connected low-pass filter, an amplifier limiting device, an integrator, a constant component filter, a detector, a differentiating device, a Walsh function generator, and n parallel-connected channels, each of which consists of connected multipliers, an integrator with an adjustable time constant, and a registering device, with the second inputs of the multipliers connected via an inverter and the third inputs are directly with a power amplifier, the input of which is connected to the source of the signal under study 2 j.

A disadvantage of the known device is the limited accuracy of measurements when changing the repetition period of the input signal, otherwise the fundamental frequency may leave the low-pass filter passband.

The purpose of the invention is to improve the measurement accuracy.

This goal is achieved by the fact that the analyzer contains quasi-periodic signals containing n parallel connected channels, each of which consists of a series-connected multiplier, an adjustable integrator and a recorder, as well as a generator of counting pulses and a Walsh function generator, outputs connected to the first inputs of multipliers of all channels, the second inputs of which are combined and connected to the output of the inverter, and the third ones are connected to 6007. 2

The input inputs are connected simultaneously with the input of the inverter and the input of the analyzer, serially connected counter-divider, memory block are entered

5 and a comparison circuit, as well as a counter, a generator of control signals and a digital-to-analog converter, the inputs of which are connected to the corresponding types of memory block, and the output is connected to the first control inputs of adjustable integrators of all channels, while the second inputs of the comparison circuit are connected to the outputs counter whose input is connected to the output

s of the generator of counting pulses and simultaneously to the first input of the separator counter, the second input of which is connected to the clock signal input and connected to the BOTOFIM counter input, the control input of the memory unit and the first input of the control signal generator, is simultaneously connected to the input Walsh function generator, third input

5 of the counter and to the second input of the generator of control signals, one output of which is connected to the second control inputs of the adjustable integrators of all channels, and the other 0 with the control inputs of the recorders of these channels.

The drawing shows a block diagram of the proposed device.

The analyzer of quasi-periodic signals contains an inverter of 1 n parallel channels, each of which consists of series-connected multipliers 2-1 ,, .., 2-п, adjustable integrator 3-1 ,,.,

3-p with adjustable time constant and recorder 4-1, ..., 4-p, generator 5 counting pulses, counter 6, generator 7 Walsh functions comparison circuit 8, generator 9 controls; av

digital signals

a converter 10 and a serially connected counter-divider 11 and a memory block 12. The inputs of the digital-to-analog converter 10 are connected to the outputs of the memory block 12 and the first inputs of the comparison circuit 8, the second inputs of which are connected to the outputs of the counter 6, and the output is connected to the generator 9 pack {} auxiliary signals

generator 7 Walsh functions and a zero input of counter 6, a counting input connected to the generator output 5 counting pulses and a counting input of counter divider 11. The outputs of the generator 7 Walsh functions are connected to the first inputs of multipliers 2-1, ..., 2 -n, the second inputs connected to the output of inverter 1, and the third to the input of the inverter 1.Odi from the generator outputs 9 control signals connected to the control inputs of the recorders 4-1, ..., 4-n, and the second output - with the first control inputs of the integrators 3-1, ..., З.-п, connected by the second control inputs to the output of the digital to analog converter 10. The control inputs of the counter 6, the generator 9 of the control signals, the counter-divider block 11 and memory 12 are connected to the input of the synchronization of the entire device. The device works as follows. The investigated quasi-periodic signal is fed to the input of the inverter 1. A clock signal arrives at the device synchronization input, the repetition period of which is equal to the repetition period of the signal being studied. In the case of the analysis of quasi-periodic signals, the sync signal can almost always be formed by the device — the source of the signal being studied. So, for example, during a periodic periodic mechanical scan, a sync signal can be formed with a sync contact, when analyzing a television signal with signals of the beginning and end of a television frame, etc. The clock signal with its leading edge zeroes and starts counter 6 and counter divider 11., the counting input of which receives pulses at the end of the i-ro period T at the output of counter-divider T.11 sets a number, mf where m is the number of equal oo the duration of the intervals, which is necessary to divide the period. The next pulse of the sync signal rewrites this number into the memory block 12, zeroes again and starts the counter-divider 11 and the counter 6, the outputs of all the registers of which are connected to the second inputs of the comparison circuit 8. Further, at the moment of coincidence of the numbers on the counter 6 and block 12, the output pulse counter 6 is formed at the output of the comparison circuit 8. Since f. 07 the first inputs of the comparison circuit 8, the number N. is applied, then during the period T.j, oHa will form m equal-length reference pulses from each other. Thus, in each study period, the comparison circuit 8 generates m reference pulses according to the magnitude of the previous period. And since the repetition period of the input signal changes slowly, there is practically no error in the analyzer due to the difference in the current period. repetition of the input signal and the current period of decomposition of this signal according to the Walsh function. The reference pulses are fed to the generator 7 of the Walsh functions and to the generator 9 of the control signals, the first of which forms the specified functions, and the second - the pulses of overwriting and Reset. A rewrite pulse is generated at the time of arrival of the last mth reference pulse, or at the time of arrival of the next clock pulse. -If the previous period T is somewhat shorter than the subsequent one, then the th reference pulse and the rewrite pulse are generated by it earlier, if the same previous pulse is slightly longer then, then the sync pulse is generated and the rewrite signal is formed by it. Pulse duration Pere-. recording does not exceed 0.1-0.5 μs. # 1 Pulse Reset is generated at the moment the pulse ends. Overwrite and serves to zero the adjustable integrators 3-1, ..., 3-p. Its duration is determined by the integrator capacitance of the integrator and does not exceed 0.5% of the input signal period. The Walsh functions arrive at the first inputs of the multipliers 2-1 ,,.., 2-n, the second inputs of which receive the input inverted signal, and the third inputs receive the input inverted signal. The products of the signals in the multipliers are inverted over a period by the integrators 3-1, ..., 3-p. At the time of the end of the period by impulse. Overwriting the signals of the integrators 3-1, ..., 3-n are rewritten in the recorders 4-1, ..., 4-p. . . Then, with a pulse, the reset of the integrators is zeroed and the integration of the next period of the input signal begins. Thus, by the end of each period, the formed in-,

The tegrato 3-1, ..., 3-n input factor decomposition coefficients in the Walsh series are rewritten into recorders 4-1 ,, .., 4-p.

When the input signal repetition period changes, the input signals of the integrators 3-1, ..., 3-n will also change. To eliminate this effect, the time constant of the integrators is made dependent on the repetition period of the input signal. To this end, the output signal from memory block 12, proportional to the repetition period of the input signal, is converted to analogue voltage, voltage 10; served on the second controls. the input of the integrators 3-1, ..., 3-n, and changes the time constant of the integrators, for example, by changing the resistance of the channel of the field-effect transistor.

The counting pulses received at the counting inputs of the counter 6 and the counting divider 11 are generated by the generator 5 of the counting pulses. Since it is necessary to minimize the frequency drift of the oscillator

pulses for only

one period of input signal

then stringent stability requirements

the frequency of the counting pulse generator is not presented.

Compared with the known device, the analyzer of quasi-periodic signals allows determining the decomposition coefficients in the Walsh series. Both periodic and quasi-periodic signals, since the current values of these coefficients are formed over only one

repetition period of the input signal. In addition, the separation of the input signal and the synchronization circuit has greatly improved the accuracy of the device.

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The device was manufactured in-house and used to analyze a quasi-periodic signal with a frequency of the order of 1 kHz. When the pulse frequency of the oscillator counting {wx pulses 5 MHz, errors in determining the first three coefficients of the decomposition of the input signal into Walsh's current did not occur. shawls 3%.

I

Claims (1)

ANALYZER OF QUASI-PERIODIC SIGNALS, containing η channels connected in parallel, each of which consists of a series-connected multiplier, an adjustable integrator and a recorder, as well as a counting pulse generator and a Walsh function generator, outputs connected to the first inputs of the multipliers of all channels, the second inputs of which are combined and connected with the i output of the inverter, and the third combined inputs are connected simultaneously with the input of the inverter and the input of the analyzer, characterized in that, in order to improve the accuracy of the measurement In addition, a counter-divider, a memory block and a comparison circuit are introduced in series, as well as a counter, a control signal generator and a digital-to-analog converter, the inputs of which are connected to the corresponding outputs of the memory block, and the output is connected to the first control inputs of the adjustable integrators of all channels, this, the second inputs of the comparison circuit are connected to the outputs of the counter, the first input of which is connected to the output of the counter pulse generator and simultaneously to the first input of the counter-divider, the second input is? connected to the input of the clock signals and connected to the second input of the counter g, the control input of the memory unit and the first input of the control signal generator, the output of the comparison circuit is connected simultaneously to the input of the Walsh function generator, the third input of the counter and the second input of the control signal generator, one output of which connected to the second control inputs of the adjustable integrators of all channels, and another to the control inputs of the registrars of these channels. SU ... 1166007 1 1166007