During the past few years, there has been an exponential growth in cellular telephone and pager market. In the next generation, the wireless data will be part of the communication systems. The DSP is the core of data processing unit. The application of D/A and D/A Converters in typical cellular phone is shown in Fig 1.7. It is seen that there are two different sets of data converters: voice-band data converters and high sampling rate at the radio frequency (RF) modulator. The voice band requires a low sampling (8KHz) but relatively high resolution, e.g., 13 bits. The RF section requires relatively high-speed but not high resolution, e.g. 8 bit.
The circuit designers prefer to integrate more functionalities in DSP part rather than in analog part. It results in lower number of components and in turn lower overall cost. The strategy of more integration in DSP part depends on the achievable specifications of high speed and high-resolution data converters with low power implementation for portable applications.
