US 11,870,451 B1
Frequency synthesizer using voltage-controlled oscillator (VCO) core of wideband synthesizer with integrated VCO
Byung-Kuk An, Seoul (KR); Young-Joung Hong, Seoul (KR); and Hyoung-Kyoun Park, Seoul (KR)
Assigned to VIAVI SOLUTIONS INC., Chandler, AZ (US)
Filed by VIAVI SOLUTIONS INC., Chandler, AZ (US)
Filed on Dec. 20, 2022, as Appl. No. 18/084,805.
Int. Cl. H03L 7/187 (2006.01); H03L 7/099 (2006.01); H03L 7/093 (2006.01)
CPC H03L 7/187 (2013.01) [H03L 7/093 (2013.01); H03L 7/099 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A frequency synthesizer, comprising:
a multiplier to:
receive a first signal with a first frequency that is a multiple of an input frequency of a reference signal provided to the frequency synthesizer; and
multiply the first frequency to obtain a local signal with a local frequency;
a voltage-controlled oscillator (VCO) bank comprising a plurality of VCOs, wherein a VCO in the VCO bank is selected to provide a VCO signal with a VCO frequency based on a tuning voltage; and
a phase-locked loop (PLL) comprising a phase detector, a charge pump, and a frequency divider, the PLL to:
receive the first signal and a second signal with a second frequency, the second signal comprising the local signal and the VCO signal mixed together; and
generate the tuning voltage to control the selected VCO based on a phase comparison of the first signal and the second signal, wherein
the VCO bank is on-chip in an integrated circuit (IC) with an output circuit, and
the PLL is off-chip external to the IC.