Adaptive detection of distorted digital signals

The paper describes a novel approach to the adaptive equalization of a channel, leading to an adaptive detector which promises to achieve in some applications a better performance over a slowly time-varying channel, for a given degree of equipment complexity, than is possible with the more conventional transversal-filter adaptive equalizer. The transmitted signal contains a serial stream of binary data elements which are separated into orthogonal groups. Each group of elements is detected in a single detection process. The preferred method of detection is an iterative process, which is used first to determine the element binary values in the group and then to estimate the channel impulse response. By this means the detector is adjusted after each detection process so that it follows the variations in the channel transmission characteristics. No training signal is required, except at the start of transmission.