Universal software and hardware complex for analysis of spectrum of electrical and optical signals

The result of the development by the employees of the Federal State Budgetary Educational Institution of Higher Education Volga State University of Telecommunications and Informatics of a digital analyzer of the spectra of electrical and optical signals, intended for scientific research, as well as for the use in educational process, is described. The device under development includes hardware and software. The hardware includes a low-frequency two-channel unit operating in an audio frequency range, a high-frequency unit operating in a frequency range of 10 kHz - 250 MHz, an optical unit representing an optical hybrid, i.e. a quadrature splitter of an optical signal, the spectrum of which is located near a frequency of 193 THz (light wavelength about 1550 nm), a central processing device, a synchronization unit, an interface unit, and microcomputer. The studied linear spectra: the Fourier spectrum with various windows (rectangular, modified Hann, Barlett, Kaiser window), the signal spectrum in the orthogonal Walsh basis, the signal spectrum in the basis of Haar functions, the spectrum in the modified orthogonalized basis of the Mexican Hat functions («Mexican Hat»). All algorithms and programs were pre-written and tested using the «Matlab» mathematical package, and then implemented in the C++ programming language, which is necessary to accelerate the procedure for spectral analysis of signals in real time.