Abstract: The 25 Hz offset present in the subcarrier frequency of the PAL television standard causes residual and phase modified subcarrier to be left on the luminance signal, which can produce undesirable visual artifacts in the picture. In order to filter luminance therefore without loss of resolution, an adaptive luminance filtering process and structure are provided. Due to the wide range of sample frequencies that must be dealt with, there are e.g. three separate filters available selectable under software control depending on the particular video standard being filtered, i.e. for various of the of NTSC and PAL television standards. The adaptive notch filter is switched on during times of low video transitions and is by-passed during high video transitions, thus avoiding loss of resolution during the high video transitions.

Abstract: A digital linked compressor-expander telecommunications system (Lincompex), is implemented using a general purpose digital signal processor wherein the compression and expansion functions are performed by blocks of programmed code. Input audio analog signals are converted to parallel data digital signals thereupon the digitial signals are input for processing. After processing, the resultant signals are passed to a 16-bit digital-to-analog converter where either the compressed or expanded digital voice data signal is converted back into an audio frequency analog signal for either transmission or communication on an output device.