Wayne Parham Messages: 18793 Registered: January 2001
Illuminati (33rd Degree)
Before the SMPTE color bars, there was another common test pattern, as shown below. It was used to check things like the linearity of the sweep, overall size, contrast and frequency response. Poor frequency response made lines fuzzy rather than having sharp edges and poor linearity made them spaced closer or further apart on some sections of the screen than others.