Transient suppression in television video systems

Abstract

In a television signal processing system, broadband means responsive to television video signals are provided to derive a relatively broadband signal including signal components in a frequency range between zero Hertz and a frequency f. Narrowband means also responsive to the television video signals are provided to derive a relatively narrowband signal having a peak amplitude response at a frequency between zero Hertz and approximately f and a relatively lower response at frequencies of zero Hertz and approximately f. Thresholding means responsive to the narrowband signal are provided to inhibit translation of signal portions of the narrowband signal above a predetermined threshold. The amplitude inhibited narrowband signal is combined with the broadband signal to provide an output signal having relatively accentuated high frequency components and relatively suppressed noise components. In an illustrative embodiment, delayed signals, developed at taps of a transversal equalizer included in the luminance channel of a television receiver, are combined to provide a relatively broadband signal and a relatively narrowband signal, the latter including relatively high frequency luminance signal components. The narrowband signal is processed to inhibit translation of signal portions above a predetermined threshold. The processed narrowband signal and the broadband signal are combined to provide a signal wherein relatively high frequency luminance signal components have been accentuated, chrominance signal components have been attenuated and transient noise, which might otherwise result in undesirable spots in a reproduced image, have been substantially reduced or suppressed.