Comb filter for TV receiver or video recorder - performs light density and colour carrier separation using amplitude selection stage in path of subtractive colour carrier

摘要

The comb filter provides frequency selective extraction of the colour carrier signal from the FBAS signal before subtraction from the latter. An amplitude selection stage (15) lies in the path of the subtractive colour carrier (F), only allowing passage of signal valves above a given positive threshold and below a given negative threshold. Pref. the selection stage (15) use 2 anti-parallel divides and it may allow passage of all amplitude values for the duration of the colour synchronisation signal. 4pp Dwg.No.i/