SU404023A1 - PARALLEL ANALYZER - Google Patents

Description

one

The invention relates to a measurement technique and is intended to simultaneously determine the spectral components of a periodic electrical signal.

Spectrum analyzers are known for carrying out simultaneous (parallel) analysis, comprising an orthogonal reference voltage generator, multipliers, and an integrator. Both the multiplexers are fed the test signal f / sc and the reference voltage L / on. Integrators are connected to the multiplier outputs. Frequency selectivity is based here on the direct Fourier transform of orthogonal trigonometric functions according to the formulas.

In the parallel method, the analyzer is composed of a parallel set of similar devices, where the generators have different and fixed frequencies. However, the known analyzer has a low accuracy of frequency multiplicity of frequency selective devices; it is unsuitable for apalns of signals with varying frequency and signals whose level is below the noise level.

The purpose of the invention is to improve the accuracy of the analysis of a signal with a discrete spectrum, as well as to ensure the accuracy of the analysis when changing the fundamental frequency of the signal.

For this, the analyzer is equipped with a common generator whose frequency is equal to 4 times the frequency of the highest harmonic, a serial frequency divider with multiple or relatively frequency generator orthogonal outputs connected to synchronous detectors and a common phase generator frequency tuning circuit of the common generator, first the input of which is connected with a switch to one of

O outputs are the frequency divider, the second input is to the input device, and the output is to a common generator.

The drawing shows a structural diagram of the proposed analyzer.

5 The analyzer consists of an input device 1, through which an analog signal is fed to synchronous detectors 2, each of which consists of a multiplying device 3 and an integrator 4. Multiplying devices are controlled by a generator 5 through a divider 6. The generator is connected to an input device using a circuit phase automatic frequency control (PLL) 7, which is connected 1a with

5 a switch 8 with an output of a divider 6, which equals one of the damping devices 3 of the lower or some other component of the signal spectrum. The Vx signal under investigation is fed through

0 input device, which depletes the matching of the signal source with the analyzer nodes, simultaneously (on parallel) to all synchronous detectors 2 key OTs, as well as to the phase automatic frequency tuning circuit 7. On each harmonic under investigation, two synchronous detectors 2 are used that can be aligned with orthogonal reference nanometers t / on by rectangular shape with strict symmetry for allocated cosine and sine components / (- th harmonic, respectively. The number of drug synchronous detectors is essentially unlimited and It is limited in each case depending on the presented measurement tasks.

At the outputs of orthogonal synchronous detectors, we therefore have signals containing information about the module and phase / (- th harmonic UkCOSff and L // tsinf, where L / t is the harmonic amplitude;

Ф / е - phase shift relative to the main harmonic.

The signals obtained at the outputs of synchronous detectors may need to be further processed, for example, by a one-component representation of the spectral component.

The high resolution of the proposed analyzer provides an almost unlimited opportunity to increase the time constant of the integrator 4, which is part of the synchronous detector.

The orthogonal reference voltages for controlling the synchronous detectors 2 are generated by sequentially dividing the output frequency of the oscillator 5 using discrete binary dividers, ensuring an ideal multiplicity of output frequencies with respect to the generator and between themselves. All discrete binary dividers are connected to common dividers 6. To ensure perfect symmetry and orthogonality of the reference voltages (which is required by minimizing the analysis), the generator frequency is first divided 4: 1. Based on these considerations, the frequency of the oscillator is 4-fold with respect to the highest studied harmonic. . At the corresponding two outputs of the divider 6, buttrupoch rectangular voltages with equal frequencies

with perfect symmetry and orthogonality. The nanometers from divider 6 arrive at synchronous detectors 2 and are used to control multipliers 3.

The provision of multiplicity points between the main harmonic of the signal under study and the frequency of the analyzer oscillator is carried out using the phase-locked phase PLL frequency control circuit 7.

Scheme 7 compares the frequencies of the main or quite strong other harmonics of the signal under study with the frequency of the corresponding reference pair. With the appearance of the difference in these frequencies, and this

equivalently to the frequency of the main harmonic and the frequency of the generator, a fault signal is generated, with the help of which the generator frequency is automatically tuned to the exact frequency ratio.

This ensures that the multiplicity of all reference voltages is accurate with respect to the fundamental harmonic of the signal under study.

The harmonic used to synchronize the generator does not have a phase

shift relative to the reference stress and is considered the zero phase. The phase shifts of the remaining harmonics are determined with respect to this harmonic.

NOTICE of invention

A parallel analyzer containing an input device and a set of synchronous detectors, each of which contains a sequentially multiplied multiplier and integrator, is characterized by the fact that it is equipped with a common generator with a frequency equal to four times the highest harmonic picks to improve accuracy, a serial frequency divider with multiples the relative frequency of the generator orthogonal outputs connected to synchronous detectors and a circuit for automatic phase tuning of the common

oscillator for the frequency of any investigated harmonic signal, the first input of which is connected, with the nominal power of the switch to one of the outputs of the frequency divider, the second input - to the input device, and the output - to the common

to the generator.

T