An integrated /spl pi//4-shift QPSK baseband modulator

A mixed analog-digital /spl pi//4 shift QPSK modulator IC targeting the Japanese digital personal handy phone system is reported. The chip includes modulator, root-Nyquist FIR, D/A converter and smoothing filter functions. The 13.5 mm/sup 2/ IC was fabricated in 1.2 /spl mu/m CMOS. It consumes 21 mW and operates from 3 V or 5 V supplies.<
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