In this paper, system level design techniques for companding baseband switched capacitor (SC) filters for WLAN applications are presented. With companding, no AGC is required in front of the filter. A filter prototype is designed for 802.11g receiver and simulation results show that, with careful design of the opamps, a total harmonic distortion of less than 0.5% can be achieved. A new type of companding ADCs along with the algorithm to achieve companding in ADCs is proposed. It is shown that companding by a factor of 4 reduces the power consumption of the SC filter by a factor close to 4 times for a given dynamic range whereas it directly results in 12 dB reduction in the dynamic range requirement of the following ADC.
Download Full PDF Version (Non-Commercial Use)