METHOD OF AMPLIFYING AND DEMODULATING FREQUENCY-MODULATED SIGNALS AND DEVICE FOR ITS IMPLEMENTATION Russian patent published in 2025 - IPC H03D3/00 

FIELD: radio communication.

SUBSTANCE: method of amplifying and demodulating frequency-modulated signals is based on using energy of a constant voltage source, interaction of a frequency-modulated signal with a device, which is made from a direct transmission circuit in the form of a three-pole nonlinear element, reactive four-terminal circuit, external feedback circuits, low-pass filter, separating capacitance and low-frequency load, compliance with matching conditions, conversion of frequency-modulated signal, spectrum splitting, selection of low-frequency component, eliminating the constant component and obtaining a low-frequency signal at the low-frequency load. As an external feedback circuit, a complex four-terminal circuit is used, which is connected in series to a three-pole nonlinear element, three-pole nonlinear element and the feedback circuit as a single unit are cascaded between the frequency-modulated signal source with a complex resistance and the input of the reactive four-terminal circuit, between the output of the reactive four-terminal circuit and the low-pass filter, a high-frequency load in the form of a two-terminal circuit with a complex resistance is switched on. Magnitudes of the modulus and phase of the transfer function are selected based on the condition of generating a given steepness of the quasi-linear section of the left-hand slope of the amplitude-frequency characteristic of the device in a given frequency band which coincides with the range of variation of the frequency of the input frequency-modulated signal.

EFFECT: amplification and frequency demodulation of a high-frequency signal.

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