A single-chip 2.4-GHz direct-conversion CMOS receiver for wirelesslocal loop using multiphase reduced frequency conversion technique

摘要

A single-chip direct-conversion CMOS receiver for 2.4-GHznwide-band code-division multiple-access wireless local loop (WLL) isndescribed. The chip includes a low noise amplifier, a 12-phasendownconverter, a variable gain amplifier, a gm-C channelnselection filter, a programmable phase-locked loop for seven channelnfrequencies, and a 4-bit flash analog-to-digital converter. The proposednmultiphase reduced frequency conversion scheme combined with anmultiphase sampling fractional-N prescaler, a cascaded dc-offsetncanceler and distributed automatic gain control loops offers solutionsnto problems of a direct-conversion receiver. Experimental results shown-115-dBm sensitivity, 4.4-dB noise figure, and 95-dB dynamic range,nwhich sufficiently meet commercial WLL specification