Colour TV signals transcoding system - separates chrominance signal and mixed signals by NTSC method, and passes them through band-pass filter and again mixes them

摘要

A chrominance signal is separated from the colour t.v. signals and is mixed with a carrier whose frequency changes in alternate lines between single and three times the colour carrier frequency (NTSC). Mixing products corresponding to twice the colour carrier frequency, together with their sidebands, are passed through a bandpass filter and are mixed with a further carrier whose frequency fn = (n-1/4) fH, where fH is the line frequency, and n is an integral number corresponding to the definition of the colour carrier frequency in accordance with the first standard with fSC = (n-1/2)fH.