Abstract: In a serial link in which it is necessary to occupy the link before and after transmission of a frame by sending a succession idle characters having alternating disparity effects, the disparity effect of the last character in the frame is compared with the disparity effect that would be produced by a disparity flip-flop, which has continued to step during frame transmission. If the disparity effect of these two characters match, no corrective action is required in order to resume the stream of idle characters. If the disparity effect of these characters differ, the disparity flip-flop is corrected before the stream of idle characters is resumed. Disclosed is hardware logic to accomplish this disparity control following transmission of frames in a transparent mode.

Abstract: The invention features a method and apparatus for improving data transmission in a transmission system having an analog signal transmitter directly connected along a transmission link to an analog signal receiver having a threshold element for detecting the signal. The invention features clamping voltages appearing at an input of the receiver symmetrically about a threshold value of the threshold element.

Abstract: An apparatus for compensating for signal distortions in an input digital signal, such as a pseudo video scan line having a television video scan line format and capable of comprising a complete self-contained packet of digital information sufficient to provide an entire video displayable row of video data characters, said signal comprising a plurality of ones and zeroes defining the digital information therein, the pseudo video scan line having associated peak-to-peak signal levels respectively defining the ones and zeroes wherein the signal distortion in the signal comprise the respective peak-to-peak signal levels associated with at least some of the plurality of ones and zeroes differing from the respective peak-to-peak signal levels associated with others of this plurality, the peak-to-peak signal levels resulting from zero-to-one and one-to-zero transitions in the signal, provides a compensated output digital signal from the distorted input digital signal having the same information content wherein the p