Flexible baseband Low-Pass Filter and Variable Gain Amplifier for Software Defined Radio Front End

Analog blocks intended for software defined radio have to be targeted to multi-standard operation trying to guarantee at any time a near optimal power-performance trade-off. A novel approach to design a digitally programmable low pass filter (LPF) and variable gain amplifier (VGA) is here defined. These baseband blocks are driven by a network-on-chip that is able to set performances like cut-off frequency, selectivity, noise, and gain conveniently adapting the power consumption. The LPF provides a wide frequency tuning range between 0.35MHz and 23.5MHz with an adaptive integrated noise level between 85muVrms and 163muVrms and a current consumption that moves from 1.5mA to 18mA. The VGA is made up of 2 cascaded gain stages and provides a gain range from 0dB to 39dB. The prototype was realized in 0.13mum CMOS technology. Measurements results validate the adopted approach