Quantum Data 801GC, 801GF, 801GX manual Timing Parameters

Timing Parameters

HRAT, sets the horizontal scan, or line, rate of the format. This is the rate at which horizontal video lines are produced. The 801G* uses Hertz as the unit of measure while most display spec sheets may give the rate in kilo-Hertz. The rate can easily be entered as a floating point number. For example, a 15.73426374 kHz horizontal rate could be entered as 15734.26374 or as 15.73426374E3. Here are some ways to calcu- late the value for HRAT if it is not given on your spec sheet:

•If a spec sheets gives you the total horizontal period, in micro-seconds, instead of the hori- zontal rate. HRAT can be calculated as follows:

HRAT = 1 / Horizontal Period

•If a spec sheets gives you a dot clock or pixel rate and the total number of active and blanked pixels per line. HRAT can be calculated as follows:

HRAT = Pixel Rate / Total Pixels per Line

The HRES parameter sets the number of active pix- els in a single scan line. This parameter may be called “Horizontal Resolution” or “Horizontal Active Pix- els” on your spec sheet.

The HTOT parameter sets the total number of pix- els (active + blanked) in one horizontal scan line. It must be an even number. If your spec sheet gives you the horizontal period in units of pixels, use this value for HTOT. Here are some ways to calculate the value for HTOT from other data on your spec sheet:

•A spec sheet may give you the number of horizontal active and blanked pixels as two separate numbers. Simply add the two num- bers together to get HTOT.

6-50 Chapter 6: Programming Model 801GC, 801GF & 801GX¥Rev. A