Flicker fixer

A flicker fixer or scan doubler is a piece of computer hardware that de-interlaces an output video signal.

The flicker fixer accomplishes this by adjusting the timing of the natively interlaced video signal to suit the needs of a progressive display for example a CRT computer monitor.

The fields switch every 60th of a second on NTSC, or 50th of a second on PAL, which allows for higher resolution while using a narrower signal bandwidth than full 50 or 60 FPS progressive video would require, but it can also produce an alarming jittering effect for graphics with high contrast details between fields.

This NTSC/PAL compatibility gave the Amiga a distinct edge in uses such as television production and gaming, but since the original Amigas were unable to produce vertically high-resolution displays without flickering this was unsuitable for office-like usage where one might need to work with a clear high-resolution image for several hours.

Also, the earlier A2024 'Hedley' greyscale monitor featured an integrated flicker fixer, supporting up to 8 shades of grey.