作者： Frank W Singor
DOI:
关键词: Oversampling 、 Electronic engineering 、 RF front end 、 Digital down converter 、 Delta-sigma modulation 、 12-bit 、 Computer science 、 Frequency multiplier 、 Cordless 、 Band-pass filter
摘要: This thesis demonstrates that analog-to-digital (A/D) conversion at the intermediatefrequency stage of a radio is feasible for wide range cellular and cordless telephony standards. Placing A/D converter as close possible to front end has manufacturing advantages allows use sophisticated DSP algorithms which are especially usem with digitally coded transmissions. The type proposed switched-capacitor (switched-C) implementation bandpass delta-sigm& (BPAZ) modulator. adhsses performance BPAZ converters by focussing on larger bandwidths (1.2MHz) higher centre frequencies (2OMHz) than previously obtained, while maintaining 12 bit resolution. An 8*-order 3-level BPAX modulator designed meet these specifications. Through modelling simulation, it shown low oversampling ratios large gains in signal-to-noise ratio cannot be obtained when going higher-order modulators. However, increasing number levels quantizer, thg can gnzatly enhanced taking advantage added stability. Two 2nd-order prototypes were implemented 0.8pm BiCMOS process determine maximum sampling frequency obtainable switched-C technology. two structures both fi~lly differential OTh continuous-time common-mode feedback, but employ different clock phasing experiment trade-offs between active passive sensitivities. analysis effects nonideal OT& biquads done compared experimental results very good correlation.