TABLE OF CONTENTS Digital wireless systems such as GSM are in wide use worldwide and will continue to expand and replace the remaining analog systems at an increasing rate. The technical factors that have contributed to this success are fundamental capabilities such as easy use of SSB (single-side-band) signals, efficient channel multiplexing (time or code division), increased capacity through compression, resilience against interference and noise, and secure transmission. In addition, the development of relatively inexpensive and low-power wireless transceivers has triggered a great proliferation of consumer portable units. Several key technologies are enabling the successful design and manufacture of these devices. Examples include GHz-band Si RF ICs, mixed-signal CMOS VLSI ICs, high-quality RF and IF passives, inexpensive plastic packaging, and DSP-based processing.
The block diagram of a typical modern transceiver is shown in Fig. 9.1. It consists of analog RF, IF, and baseband sections and a digital section. The analog/digital interface (i.e. A/D and D/A converters) is placed at baseband, a choice dictated primarily by cost and power dissipation considerations. Despite the usual preference for "digital whenever possible" designs, it is still to be shown that moving the analog/digital...
