With modern SVGA multiscan monitors, once a particular resolution and scan rate is set up, there is rarely a need to readjust size, position, and other parameters. How is this accomplished?

(From: Bob Myers (myers@fc.hp.com).) It's different for different designs, of course, but in general today's 'digitally controlled' monitors recognize various timing modes by counting the horizontal and vertical sync pulses to determine the line scan and vertical refresh rates. Any input within a certain tolerance of a recognized pair of frequencies here is assumed to be that timing, and a set of stored numbers corresponding to that timing are then read from a memory and used to set up the adjustments. In most of these monitors, the various adjustable parameters - size, centering, etc., - are controlled by voltages coming from a set of D/A converters, so the stored information is basically just a table of numbers that get sent to the D/As when that timing is recognized. The number of both factory and user presets available varies from product to product, of course, but there's usually somewhere between 8-15 of each. The exact number is going to depend on how much memory is available, ...  more