[EE 284] - Final Exam Guide - Everything you need to know! (66 pages long)
Document Summary
Study guide the lower the bandwidth, the lower the quality. G. 711 has two variants: a-law and m-law. m-law is used primarily in north america and a- law is used in most other countries. Both a-law and m-law provide very good quality and have an mos of about 4. 3. So in dpcm the difference between the predicition and actual signal is sent to the other end, where the other end can predict the actual signal on the basis of the difference between them. A slightly more advanced version of dpcm is adaptive dpcm (adpcm). Adpcm typically predicts samples" values based on past samples while factoring in some knowledge of how speech varies over time. The error between the actual sample and the prediction is quantized, and this quantized error is transmitted to the far end. Assuming that predictions are fairly accurate, then fewer bits are required to describe the quantized error and hence the bandwidth requirement is lower.
