In this research, a new and simple automatic frequency-tracking scheme for direct conversion BPSK modified DS/FH-CDMA system operating at 2.4GHz ISM band in the presence of large carrier frequency offset is proposed. With this technique, the proposed transceiver architecture can keep track of incoming carrier frequency for coherent demodulation without prior notice. A primary and secondary frequency tracking system allows a rapid locking (...[ Read more ]

In this research, a new and simple automatic frequency-tracking scheme for direct conversion BPSK modified DS/FH-CDMA system operating at 2.4GHz ISM band in the presence of large carrier frequency offset is proposed. With this technique, the proposed transceiver architecture can keep track of incoming carrier frequency for coherent demodulation without prior notice. A primary and secondary frequency tracking system allows a rapid locking (< 3μs ) for frequency offset below 500kHz and a guaranteed locking speed within 90μs for each tracking step. Simulation results show that the frequency-tracking scheme works well in the presence of any frequency offset in the 2.4GHz ISM band with PN code mismatch. The transceiver has also been designed to suit for complete monolithic integration and is intended for telemetering application with chip rate of 10Mcps and data rate of 333kbps. In the proposed system, frequency offset correction is done in analog approach and PN correlation in semi-digital approach. Specifications and design considerations of each building block will be given with respect to the proposed direct conversion transceiver.