Earticle

This paper is a humble step towards investigating feasibility of implementation of Code Excited Linear Prediction algorithm on Adaptive Multi Rate Wideband coder over audio signals. Proposed coder offers inherent capability of adaptively change its bitrates with variation in received C/I ratio depending upon channel conditions. Though proposed WB coder exhibits nine different bitrate modes (between 6.6kbps and 23.85kbps), its practical implementation reveals that only two upper most bitrates (which are 23.05kbps and 23.85kbps) have been found suitable for audio transmission and recovery over WB link. An e-test bench using MATLAB is created to implement proposed WB coder and series of simulations are carried out to judge the performance of implemented coder for audio signal using Subjective (Mean Opinion Scores) and Objective (Perceptual Evaluation of Audio Quality- Objective Difference Grade) analysis. Simulation results clearly advocate that it is possible to reproduce audio signals with comparable quality when implemented with upper most two bitrates of AMR WB coder. It is also evident from the obtained simulation results that PEAQ and MOS for chosen audio signal are also quite comparable and satisfactory.