Delay Distortion and Signal Impairment in Digital Data Transmission

摘要

Attempts to enhance the transmission rate of digital information through communication channels have imposed increasingly stringent tolerances on the equalization of signal distortion. A primary source of system degradation and signal impairment which has impeded signaling rates is the envelope delay inherent in the data channels. Since the distortion accompanying a nonuniform envelope delay transmission characteristic can limit the imagery acutance of graphical displays, can lead to read-write errors during data storage and retrieval in tape systems, and can cause misinterpretations of digital baseband signals by generating intersymbol dependencies, delay distortion has been a subject of renewed inquiry. Some of the physical and analytical aspects of envelope delay were examined in order to afford further insight into the nature of delay distortion. Various combinations of signal waveforms and system delay distortion were explored which are encountered in practical situations. Although neither an algorithm for delay equalization was formulated, nor a critique given of the few available techniques of delay equalization, several computational desiderata are outlined, and a deeper understanding of the significance of delay distortion provided. (Author)