quality measures. Firstly, the implementation of subband coding techniques in speech and audio signal coding will be presented. Subband coding performs decomposing of the imput signal into subbands, which can be coded independently, by witch we can reduce the required bit rate. Four different subband coding algorithms will be presented, determined by different complexity levels and quantization techniques. This dissertation will present modified BTC(Block Truncation Coding) algorithm and its implementation in speech and audio signal coding. BTC algorithm was originally developed for applications in black and white image coding, while the modified algorithm exploits some of the common characteristics of black and white images and speech and audio signals. Also, a simple differential and backward adaptive coding algorithm will be presented. This algorithm will show the advantages of implementing aforementioned techniques, by witch we can obtakin high output signal quality, while preserving low computational complexity. ...