Design of a selective digital filter using the decimation technique

The implementation of an Intermediate Frequency (IF) filter in Digital Audi o-VIsual Council (DAVIC) compliant modems is a particularly complex task. I n previous works, we compared the performance of different designs (analog and digital) for the radio-frequency stage in a modem application. These de signs have been evaluated for a particular case defined in the DAVIC recomm endation. The design limits that were pointed out are mainly due, in the di gital approach, to the high frequencies at which the IF stage must operate, and to the variation of the sampling frequency. In this paper, we propose a digital implementation of the IF filter based o n the decimation technique. The evaluation of the performance has been perf ormed using the PTOLEMY software from the Berkeley University. (C) 2001 Pub lished by Elsevier Science Ltd.