METHOD OF DETERMINING FREQUENCY AND TYPE OF MODULATION OF RECEIVED SIGNALS Russian patent published in 2008 - IPC G01R23/14 

FIELD: radio electronics.

SUBSTANCE: method can be used for determination of carrier frequency and type of modulation of signals received within specified frequency range. Method of determination of frequency and type of modulation of received signals is based upon search of signals within specified frequency range due to re-tune of super-heterodyne receiver, upon formation of frequency roll-out onto screen of cathode-ray tube, transformation of frequency of received signal and amplification of its voltage, detection and application of signal to vertical-deflecting plates of cathode-ray tube. As a result, pulse is formed onto screen, position of which pulse is used to determine carrier frequency of received signal onto frequency roll-out; effective factor of amplitude modulation, efficiency frequency deviation, spectrum width of received signal, spectrum width depending on efficient frequency deviation are determined. Efficient factor of amplitude modulation and relation of spectrum width to efficient frequency deviation is compared with specified numerical values and amplitude or angular modulation of received signal is determined. Detected video signal is subject to integration and comparison with threshold voltage. In case threshold voltage exceeds, frequency of heterodyne is measured at given moment of time. Code of heterodyne frequency, measured at given moment of time, is compared with codes of heterodyne frequencies measured before. In case the codes to be compared are not equal, specific types of modulation of received signal are provided, video signal is applied to vertical-deflecting plates of cathode-ray tube and code heterodyne frequency, measured at that specific moment of time, is memorized. Excess information can be removed due to exclusion of repeat measurement and registration of carrier frequency in form of modulation of continuous signal to be received.

EFFECT: improved reliability of operation.

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