COTS based multichannel FM receiver and recorder using SDR concept

Abstract

Broadcast FM radio is low cost, portable and omnipresent source of information and entertainment in the urban as well as rural areas of developing countries. Regulatory authorities require an efficient and low-cost system to record large number of 24/7 FM transmissions to bring all the broadcast content within legal bounds so that they are not misused by the proscribed entities. In this paper we present a multichannel broadcast FM receiver and recorder based on SDR (Software Defined Radio) concept that is implemented using commercial off the shelf components (COTS). Multiple FM broadcast channels are down converted, digitized and then demodulated simultaneously. Recovered baseband audio signals are stored on hard disk with appropriate time stamps for easy on-demand retrieval and playback. The use of commercial analog RFTV tuner front-end, GNU SDR digitization board and PC makes the solution flexible, configurable, and low cost. In present form the system is tested to simultaneously receive and record up to fifteen FM radio channels. The system can be easily expanded to record all FM channels in a 88-108MHz band, just by using two RF TV tuner modules with same digitization FPGA board and PC.