Inventors:
Richard W. Citta - Oak Park IL
Ronald B. Lee - Chicago IL
Assignee:
Zenith Electronics Corporation - Glenview IL
International Classification:
H04N 704
Abstract:
A hybrid television signal of less transmission power or better signal to noise performance is made up by removing low frequency analog components from the video signal, digitizing them and sending them as data in non-active video portions of the transmitted signal. A two step hybridization process, with the first step removing the line averaged value of the video components of the video signal and the second step removing the remainder of the video components under 200 KHz, is described. Temporal filtering, signal pre-emphasis, compression, time dispersion and double sideband suppressed carrier modulation about a centered carrier are disclosed for reducing peak signal amplitudes and for minimizing co-channel interference to and from NTSC signals. Time dispersion is done horizontally, vertically or both to reduce the peak signal amplitudes. Time dispersion in conjunction with low frequency removal and temporal filtering is preferred.