Implementation of code tracking loop for PCS system

In spread spectrum systems PN code tracking is a crucial element in system performance. This paper describes design and implementation of a code tracking and data demodulation module for wideband CDMA PCS system using FDDLL technique. We have implemented code tracking and data demodulation module using FPGA and DSP to facilitate flexible change of system parameters. Operation of the proposed code tracking loop is analyzed numerically over AWGN channel. Expected value of the discriminator output yields an S-curve. Timing simulation of the proposed system is performed to verify proper operation. The implemented code tracking and data demodulation module operates at 4.096 MHz PN code rate. In loop-back call test, reconstructed speech shows toll quality.