Technology of Q 2500 colour TV set

Technology of Q 2500 colour TV setKfactor10,750,500,250K factor0 > 0 NoiselevelIn the other extreme case K = 0, only the delayedsignal would be switched, which wouldcorrespond to a freeze frame. To avoid thisthe K factor in our TV sets can never be 0.Otherwise it would only be programmes with aweak signal that would be incapable of beingdisplayed.4.5.2 Line interpolationInformation about the size of movement isprovided by the movement detection. Thisoccurs only in the Y branch, with which the Kfactor is set simultaneously for chroma and Y.The drawing shows the DNR principle for theY path. As already mentioned the circuit in thechroma path is identical. The K factor canhave a value from 0 to 1. At K = 1, 100% ofthe direct signal and 0% of the delayed signalis switched to the following "And". No noisesuppression is therefore available.The line interpolations circuits allow a situationto be achieved in which a full-line picture iswritten for PALplus signals . The advantagewith respect to a PALplus decoder is that evenwithout a PALplus signal, the interpolation inall zoom modes delivers a full-line picture.This function is explained in the followingparagraphs for PALplus, in the zoom functionsthe circuit operates similarly only with otherfactors.Standard PAL signalPALplus signalPALplus signal on 16:9-c.r.t. with line interpolation72 lines black bar576 linesvisible picture432 linesvisible pictureInterpolation576 linesvisible picture72 lines black barA standard PAL signal consists of 576 visiblelines. For PALplus, 144 of the lines are darksampled and only 432 lines are transferred asa visible picture. In 16:9 c.r.t’s these signalsare shown in the ZOOM mode. In order todisplay 576 lines the information for 4 linesmust be determined by 3 lines respectively.This computer operation is verycomplicated and will therefore not be explainedhere.Line interpolation must be carried out both inchroma as in the Y branch.Document Q 2500 98 © Loewe ProCollege