Adaptive subband coder design for HDTV signal transmission

An adaptive subband coder design for high-quality high-definition television (HDTV) signal transmission through single or multistage coding is presented. In the coder, quadrature mirror filters (QMFs) decompose the input signal into four bands. An adaptive discrete cosine transform is adopted for horizontal-low and vertical-low signal coding. One-dimensional differential pulse-code modulation (DPCM) coding is applied to the signals on the same horizontal line of the horizontal-low and vertical-high band. The other band signals are coded by PCM having a dead zone. Computer simulation results are presented in terms of bit per pel and the quality of the reconstructed picture. The causes of quantization-noise accumulation in tandem connections are also investigated. A coder configuration that reduces noise accumulation is presented