METHOD TO MEASURE RADIO SIGNAL FREQUENCY IN ACOUSTOOPTICAL RECEIVER - FREQUENCY METER Russian patent published in 2014 - IPC G01R23/17 

FIELD: measurement equipment.

SUBSTANCE: invention relates to radio measuring equipment. Method to measure radio signal frequency in an acoustooptical receiver -frequency meter involves delivery of the radio signal to be analysed to the electric input of the acoustooptical deflector, its conversion into an acoustic and then an optical signal, Fourier conversion of the latter with the fixation of its intensity distribution by a N-element linear photodiode array, formation of video signals at the photodiodes' outputs with the video signal levels proportional to the said intensity distribution, calculation of the radio signal frequency identifiable with the abscissa of the intensity distribution symmetry axis of a light signal sampled by the photodiodes, delivery of calibration signals to the deflector input along with the signal to be analysed, identification of the photodiodes in the array that responsed to the calibration signals, identification of maximal level among the signal responses, recording of numbers of photodiodes corresponding to them and measurement of signal levels both at them and at the photodiodes set near them, usage of these data to calculate frequencies corresponding to the numbers of photodiodes with maximal signal levels, performance of the above operations for the photodiode responses for R (where R>2) calibration signals, with the frequencies of the latter F₁, F₂, …, F_j, …, F_R being evenly distributed in the frequency range of a frequency meter and increasing as the index increases, marking of the found photodiode numbers with maximal signal level n_j (where(1≤j≤R), marking of signal levels at them and at the neighbouring photodiodes Y_nj, Y_nj+1, Y_nj-1 respectively, calculation of factors k_nj, calculation of frequency spacings ΔF_j in frequency bands f_j…f_j+1, where the frequencies f_j=F_j-k_njΔF_j correspond to the photodiodes with the numbers n_j, following identification of frequencies f_q=f_j+ΔF_j-(q-n_j) corresponding to q photodiodes (where n_j≤q≤n_j+1) and used to calculate the abscissa of the above symmetry axis.

EFFECT: improving radio signal frequency measurement accuracy.