A Second-Order Antialiasing Prefilter for a Software-Defined Radio Receiver

A new architecture is presented for a sinc
²
(f) filter intended to sample channels of varying bandwidth when surrounded by blockers and adjacent bands. The sample rate is programmable from 5 to 40 MHz, and aliases are suppressed by 45 dB or more. The noise and linearity performance of the filter is analyzed, and the effects of various imperfections such as transconductor finite output impedance, interchannel gain mismatch, and residual offsets in the channels are studied. Furthermore, it is proved that the filter is robust to the clock jitter. The 0.13- mum CMOS circuit consumes 6 mA from a 1.2-V supply.