A method for multiphase signal generation by means of coupling several identical cross-connected LC-VCOs via capacitors is presented. An analysis is presented which shows that there is a 180/N degrees phase difference between the outputs when N identical oscillators are coupled to each other. Since there is no noise and power consumption introduced by the coupling capacitors, the circuit has a better phase noise performance and lower total power consumption than other similar multiphase oscillators. Simulation results for the oscillator designed with a 0.18 µm CMOS technology are presented and compared with another similar multiphase oscillator.

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