This project is the result of a visit by the author to a friend’s home to see a video recorder and portable TV in which the picture was "flickering" and the brightness varying.

It transpired that the problem was caused by something called "Macrovision", which is a VCR-to-VCR copy-prevention system. This purposely introduces interference pulses on the video tape. Generally speaking these interference pulses don't cause any problems, but in some cases they can interfere with the picture quality.

This PIC-based project is designed to remove the interference pulses (and to replace them with an appropriate DC level, since the TV or VCR requires a reference voltage to set its brightness).