A Two-port GFSK Direct Modulator for Wideband Applications at 5.8 GHz

Wireless audio applications at 5.8GHz require a wide band GFSK modulator with small distortion and very low power consumption. The traditional open loop modulation technique is susceptible to pulling. More advance close loop modulation requires precise calibration to match gains of analog and digital predistortion paths. The authors demonstrate a direct GFSK modulator at 5.8GHz with low power consumption using 0.18 mum SiGe BiCMOS technology. The technique is not based on predistortion of the digital signal and therefore does not require an exact match between transfer functions of digital and analog paths.