CMOS零中频接收机片上系统直流偏差的消除

DC-Offset Cancellation in CMOS Direct-Conversion Receiver SOC

针对CMOS直接下变频接收机片上系统,提出了采用系统优化设计与数字校正的综合方法来解决系统中的直流偏差问题.通过降低混频器开关级晶体管的偏置电流和片上系统技术的优化设计,将由器件不匹配和本振自混频造成的直流偏差控制在数字校正可以解决的范围内,在低功耗的前提下,通过数字校正的方法就可以进一步将直流偏差控制在系统允许的范围内.测试结果表明该方法有效.

A comprehensive method of system optimum design plus digital calibration to resolve DC-offset of CMOS direct-conversion receiver system-on-chip（SOC） is proposed.By reducing direct-current（DC） through local oscilator（LO） switch transistors in mixers and designing system layout optimally,the DC-offset resulting from transistors mismatch and self mixing of LO can be reduced in the range that digital calibration can handle.Under the low power consumption restriction,DC-offset can be controlled in an allowable range by means of digital calibration.