Programmable analogue baseband filters for software defined and cognitive radio

Analogue baseband filters are an important circuit for channel select and anti-aliasing in wireless and mobile communication systems. For software and cognitive radio, they must be widely tunable and reconfigurable to accommodate existing, emerging and future wireless and mobile standards. In this paper, design considerations of programmable analogue baseband filters for highly-integrated multi-standard receivers are presented. Design challenges, filter structures and circuit techniques (active-RC and g_m-C) are described. On-chip tuning methods are also discussed.