MULTIPHASE CLOCK GENERATOR

摘要

A reference clock of frequency F is used to generate a quadrature clock at the same frequency F without generating frequencies higher than F. A multiphase voltage-controlled oscillator (MVCO) has a nominal frequency less than F is used in a feedback circuit with a multiple phase (MP) phase detector that which operates on the multiple phases of the MVCO. The multiple phases of the MVCO are sampled at and latched on both edges of the reference clock to generate phase detector outputs which are combined in combinational logic to generate Sync State outputs. The Sync State outputs are used in combination with the multiple phase outputs to generate an error signal with is operable to generate a control voltage which controls the frequency of the MVCO and to generate a shifted clock which is divided in a sequential circuit to generate the quadrature clock with a frequency F. An MVCO with a different nominal frequency 2F is used in conjunction with alternate logic to generate twenty phases of a reference clock of frequency F.