The test pattern is designed in such a way that when the software conditions are correct, and when the amps are tuned correctly, the circle will collapse into the square.
The pattern is designed to measure speed using the complex frequency response of the galvos. Aka the "Transfer Function" or Equation of Motion. The Circle only has a handful of points, and thus will collapse at high speeds.
Steve
Qui habet Christos, habet Vitam!
I should have rented the space under my name for advertising.
When I still could have...