BROADBAND FREQUENCY SYNTHESIZER Russian patent published in 2019 - IPC H03L7/00 

FIELD: radio equipment.

SUBSTANCE: invention relates to the field of radio equipment. To this end, a frequency synthesizer is proposed, which comprises a reference frequency source (RFS), a voltage-controlled oscillator (VCO) connected to each other by an automatic frequency control (AFC) system. Feedback loop includes a frequency divider. Synthesizer is equipped with frequency transfer device (FTD) placed at output RFS. FTD comprises series-connected first mixer, intermediate frequency filter, second mixer and comparison frequency filter. Feedback circuit additionally comprises two parallel feedback circuits. First circuit comprises a frequency multiplier and is made so that the VCO output is communicated via the multiplier with the input of the first FTD mixer. Second circuit comprises in-series connected first frequency divider with variable division factor and second multiplier and is made with provision of VCO output connection through divider and multiplier with input of second mixer FTD.

EFFECT: technical result consists in reduction of phase noise introduced by the AFC circuit.

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