An adaptive frequency calibration technique for fast locking wide-band frequency synthesizers

초록

A fast response adaptive frequency calibration (AFC) technique for wide-band frequency synthesizers is presented. In order to operate in a wide-band frequency range, digitally controlled switched-capacitors bank LC VCO is used and a wide-range digital logic quadricorrelator (WDLQ) is proposed for frequency detector. The specified VCO tuning range is as wide as 1 GHz (50 %) from 1.5 to 2.5 GHz and the VCO gain is 20 MHz/V. The CADENCE Spectre simulation results show that the proposed design can achieve a fast adaptive frequency calibration in less than 25 μs with 10 MHz reference clock, which is shortened by half in comparison with the previous works which used counters for frequency detector. © 2005 IEEE.