SU798618A1 - Spectrum analyzer - Google Patents

Description

I

The invention relates to electrical measuring equipment and can be used to measure the power spectral density of random signals.

Anaptizers of the spectrum are known &, in the Topbix, measurement of the spectral density of random signals is performed with a filtering method containing a series-connected narrow band-pass filter, a quadratic detector, an averaging device, and a recording device ij.

Since the analysis of random processes often necessitates an accurate measurement of the spectral power density of random signals, to eliminate the effect on the result, the instability of the characteristics of the anaptating channels is measured by calibrating the analyzer channels by applying white noise at its input with a known spectral density.

Also known spectrum analyzer is a parallel analysis method containing. sequentially connected switches, an input device, a group of analyzing filters with detectors and integrators, a switch, a control unit and a registering device, with the first switching input; an input signal is given, and a signal is sent from the reference generator f2.

The disadvantage of such a spectrum analyzer is manual calibration of the device, which requires long-term processing of the results manually by the operator or using mainframe computers.

The purpose of the invention is to increase the speed of the analyzer.

This goal is achieved by the fact that a spectrum analyzer containing a series-connected oscillator, an automatic switch, an input unit, a group of analyzing filters with quadratic detectors and integrators connected between the input unit and the switch, .tsi ({read counter unit and control unit, entered with the second inputs of the automatic switch and the switch, the input signal is supplied to the first input of the automatic switch, and the second signal is sent from the generator; The unchanged logarithmic analog digital converter and code subtractor, connected between the switch and the digital reading unit, and the recording unit, the input of which is connected to the output of the logarithmic-analogue digital converter, and the output to the second input of the readout code, while the control input of the remembering unit with the control unit. The drawing shows the structural diagram of the device.The spectrum analyzer contains a generator 1, connected in series automatic switch 2, input unit 3, group of filtering filters 4 with square-law detectors 5 and integrators 6, switch 7, logarithm-mini anapog-digital converter 8, subtractor 9 codes, digital readout unit 10, the input signal of the automatic switch 2 being fed to the first input and the second signal from the generator 1 as well as the storage unit 11, the input of which is connected to the output of the logarithmic analog-digital converter 8, and the output to the second input of the code reader 9, and the control unit 12. The outputs of which are connected to the control inputs th switch 2, switch 7 and the memory unit 11. The proposed spectrum analyzer is as follows. In the first cycle of operation of the automatic switch 2, controlled by the control unit 12, a noise with a known spectral density from the control oscillator 1 is supplied to the inputs of the analyzing filter groups 4. At the same time, the rms voltage of the outputs of the integrators 6 are equal to%. . at П i, 2, 3 where Y is the number of analyzing channels; $ gj, is the energy bandwidth of the analyzing filters 4; KVI - the transmission coefficient of the analyzing channel. These voltages through the switch 7 are sequentially input to the logarithmic analog-to-digital converter 8 and converted into codes whose numerical values are equal to ku, where Kg is the slope of the analog-to-digital converter 8. According to signals from the control unit 12, these codes are transferred to the storage unit 11. In the second cycle, according to the signal of the control unit 12, the automatic switch 2 is moved to another position. In this case, the input test voltage Ugx enters the input of the analyzing channels. power spectral density IV. Then, through the switch 7, the output voltage of the channels is sequentially converted into codes whose numerical values are%., 5e.,% .. at the end of the second clock cycle, according to the commands of the control unit 12 in the code subtractor 9, the corresponding codes are read from the N xvi codes previously recorded in the storage unit 11. As a result. in the output register of the subtractor. 9 codes will be fixed codes whose numerical values are equal,. N; ,,% v. These codes, LO, correspond to the values of v of the spectral platitude of the input signal power, are indicated by a digital from the :: even block Y in decibels. The results of the measurement of the spectral lot of the power of random signals

do not depend on the instability of the transmission coefficients of the conversion channels and on the instability of the energy bandwidth of the analyzing filters.

Invention formula

A spectrum analyzer containing a series-connected generator, an automatic switch, an input unit, a group of analyzing filters with quadratic detectors and integrators connected between the input unit and the switch, a digital readout unit and a control unit associated with the second inputs of the automatic switching of the bodies and the switch, The first input of the automatic switch is given an input signal, and the second is supplied with a c /; "signal from the generator, characterized in that The consecutively connected logarithmic analog-to-digital converter and: a code subtractor connected between the switch and a digital reading unit, and a storage unit whose input is connected to the output of a log-analogue-digital converter, and the output to the second input of the code readouter, while controlling the input of the remembering unit is connected to the control unit.

Sources of information taken into account in the examination

1. Mirsky G. Ya. Instrumental determination of the characteristics of random processes. M., Energie, 1972. p. 234-247.

2. USSR author's certificate

No. 468181, cl. Q O1 R 23/165, 1975.

Claims (1)

Claim A spectrum analyzer comprising, subsequently connected, a generator, an automatic switch, an input unit, a group of analyzing filters with quadratic detectors and integrators connected between the input unit and the switch, a digital readout unit and a control unit associated with the second inputs of the automatic switch and switch, moreover, an input signal is supplied to the first input of the automatic switch, and a signal from the generator to the second input, characterized in that, in order to increase the speed of operation, it introduces given are the logarithmic analog-to-digital converter connected in series and: a code subtractor connected between the switch and the digital readout unit, and a storage unit whose input is connected to the output of the analog-to-digital converter, and the output to the second input of the code subtractor, while the control input of the storage unit connected to the control unit.