@article{Al-Rawi_Al-Rawi_2012, title={Comparison between Two Algorithms of 32kb/s ADPCM using QAM Signal at 16.8kb/s}, volume={4}, url={https://jtec.utem.edu.my/jtec/article/view/437}, abstractNote={This paper studies the comparison between two <br />algorithms of 32kb/s ADPCM systems. The first algorithm uses <br />4-bit quantizer with sampling rate of 8000 sample/sec, and the <br />second algorithm uses 5-bit quantizer with sampling rate of 6400 <br />sample/sec. The comparison is done using QAM signal at data rate <br />of 16.8kb/s. Two models of QAM signals are used, the first model <br />operates at symbol rate of 2400 baud with each symbol is <br />represented by 7-bit, while, the second model operates at symbol <br />rate of 2800 baud with each symbol is represented by 6-bit. The <br />contribution of this paper is that sending the second model of <br />QAM signal over ADPCM with 5-bit quantizer. Simulation results <br />show that the performance of ADPCM with 5-bit quantizer is <br />better than 4-bit quantizer for both models of QAM signals. Also, <br />the performance of ADPCM using second model is better than the <br />first model. Furthermore, the performance with circular <br />constellation is better than rectangular one}, number={2}, journal={Journal of Telecommunication, Electronic and Computer Engineering (JTEC)}, author={Al-Rawi, Muhanned and Al-Rawi, Muaayed}, year={2012}, month={Dec.}, pages={53–56} }