13-01-2011, 02:34 PM
LOYOLA INSTITUTE OF TECHNOLOGY & MANAGEMENT
Department of Electronics and Communication Engineering
Technical Seminar on
GMSK DEMODULATOR USING COSTAS LOOP FOR SOFTWARE-DEFINED RADIO
ABSTRACT
DSP based implementation of Gaussian Minimum Shift Keying (GMSK) demodulator using Costas loop has been described. The demodulator consists of a Costas loop for carrier recovery, data recovery, and phase detection. For low data rates, we have tested the scheme on a TI’s DSP TMS-320C6713. These are implemented using MATLAB and SIMULINK tools and tested on TI’s DSP using Code Composure Studio (CCS). Carrier has been recovered using a loop of center-frequency locking scheme as in Binary Phase Shift Keying (BPSK) Costas-loop. Demodulator performance for AWGN channel for different data rates is shown. Performance is measured for Bandwidth Time product (BT = 0.3 and 0.5) with data rate between 8 kbps to 256 kbps. Bit synchronization and image coding and decoding are designed according to the need of demodulator. The scheme may find its use in Software-Defined Radio (SDR) applications
Guide
D. RAKESH (M.Tech)
Asst prof
Submitted by P.V.BHARGAVI