Inventors: Richard Saylor, Alfred Dalimonte, and Robert H Nagel

US patent number:4,104,681

US patent application date: October 27, 1976
US patent issue date: August 1, 1978

SYNOPSIS OF THE INVENTION

This patent provides that a pseudo video scan line has an associated transmission time equivalent to that of the television video scan line with the packet of digital information contained therein comprising at least address information for the displayable row and data information for the displayable characters in the displayable row.

The first transmitting means transmits the first plurality of pseudo video scan lines out of phase in time in a predetermined phase relationship, such as 180 degree out of phase in the instance of two transmitting means, with the transmission of the second plurality of pseudo video scan lines by the second transmitting means with, however, the digital information content of the first and second plurality of pseudo video scan lines being substantially identical.

The television signal distribution means preferably comprises means for compensating for television transmission distortion in the provided composite combined interleaved pseudo video scan lines provided to the video display means.

This distortion compensation means comprises means for limiting the associated energy distribution of the waveform comprising the provided composite combined interleaved pseudo video scan line signal to bring this energy distribution within restrictions associated with the television signal distribution means, such as with a cable TV system if that is the means of television signal distribution utilized.

This limiting means preferably comprises a sin.sup.2 filter means for introducing a controllable distortion in the provided composite combined interleaved pseudo video scan line signal which thereby provides the energy distribution limitations.

The distribution of the controllably distorted signal through the television signal distribution means provides the composite combined interleaved pseudo video scan line signal to the receiver means substantially free of such television transmission distortion.

The distortion compensation means also preferably comprises means operatively connected to the filter means for compensating for television transmission distortions introduced by envelope detection of vestigial sideband television demodulation by providing an additional controllable distortion in the controllably distorted provided signal from the filter means.

The distribution of this additionally controllably distorted signal through the television signal distribution means provides the composite combined interleaved pseudo video scan line signal to the receiver means substantially free of such vestigial sideband demodulation distortion.