Hadamard transformation: Walsh spectral analysis of television signals

The characteristics of Walsh-Hadamard transformation systems were examined with a view to reducing the data rate of digital television signals. Transformed signals were measured using several different transformation arrangements by means of a Walsh spectrum analyzer, in which television signals are correlated with Walsh functions. It was found that a slightly higher data rate is required to describe the transform coefficients with linear coding than is needed for the original signal. A more efficient encoding of the transform could be provided using nonlinear quantization or adaptive bit-rate reduction systems. Two-dimensional transformation and the use of sampling frequencies which concentrate the energy of color signals in the transform improve the performance of these bit-rate reduction systems.