Data Converter Requirements for Communications

Summary

In this chapter, we have briefed communication-related terminologies and concepts and discussed the impacts of communication systems on data converter requirements. In order to meet a communication system specification, we have derived minimum data converter requirements that are mostly influenced by the error probability and the peak-to-average ratio. We have also discussed optimum data converters for ADSL that are a function of application environments such as the transmit power spectrum, the receive power spectrum, the hybrid rejection, and the background noise. Wideband radio for multi-channel applications are similar to DMT but with much fewer carriers. We have derived optimum A/D converter requirements for wideband radio as a function of the single carrier dynamic range, the number of channels, the noise figure, and the background noise. To apply these knowledge to a specific system, we usually need to add 1~2 bit (or even more) design margin depending on the system trade-offs. Also coding can reduce the data converter requirements by 3~6 dB, which has not been treated in this chapter but can be easily added to the equations. As far as distortions are concerned, they usually follow the SNR requirements without being effected by oversampling.