Flexible Digital-Intensive Wireless Receivers in Nanometer CMOS

Wireless receivers designed in nanometer CMOS processes should take advantage of the strengths of more fundamentally digital topologies and intelligent digital control of analog circuitry. Analog discrete-time (DT) filters show promise because these filters consist of capacitors and switches and because configurable digital sampling clocks determine their frequency responses. We first introduce a receiver in 65nm CMOS that replaces conventional integrated baseband filters with a SAR ADC with embedded DT filtering. Then we discuss an intelligent spectrum-adaptive filtering technique, which analyzes the received signal for interferers with DT spectrum-analysis filters and sets the mode of a reconfigurable filter to reject the strongest detected interferer.