SPECTRUM ANALYSER Russian patent published in 2011 - IPC G01R23/16 

FIELD: physics.

SUBSTANCE: serial-type spectrum analyser employs the principle of increasing sensitivity by picking up from the mixture of the measured signal and noise of a heterodyne the correlation component part of noise of the heterodyne in a measurement channel and transmitting said component over a feedback circuit to a control element included in the positive feedback circuit of the tunable oscillator used as the heterodyne. To this end, the spectrum analyser includes a circuit having series-connected phase changer, phase detector, low frequency amplifier with a control element, which suppress said noise in the spectrum of the generated heterodyne signal, with a level defined by amplification of the feedback circuit so as to minimise the error for measuring fluctuation at the input of the preamplifier of the analyser.

EFFECT: broader dynamic measurement range greater than 160 dB.

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