A frequency-domain equalizer with a mixed-signal adaptive control loop and a novel baseline wander （BLW） canceller are proposed. The equalizer is independent of channel-modeling accuracy,and its control loop is intrinsically stable. An AGC function is incorporated into the equalizer without an extra AGC circuit. The proposed BLW canceller uses a peak detector to monitor the BLW and full feedback method to accomplish BLW canceling. High canceling accuracy and robust performance are achieved. The circuits are tested in 0.25μm CMOS technology. Better performance and smaller silicon area are achieved compared with results in the literature.
A new FM transmitter is reported. It adopts a fractional-N PLL synthesizer to realize the FM modulator. An extra offset current has also been applied to eliminate the effects of the mismatch in CP. The chip is fabricated with CSMC 0.5μm DPTM CMOS technology. Experiments show that it achieves THD≤0.08% and SNR≤ 82dB,and the maximum outband emission energy ≤ 90dBc/Hz. Furthermore,it also uses an auto frequency adjusting method to avoid tuning up the external inductances. All these merits are very suitable for FM transmission.
