Quantum-data 801GC Manual do Utilizador descarregar pdf (Página 179)

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The VTOT parameter sets the total number of hori-

zontal scan lines, active + blanked, in one complete

frame. It must be an odd number when SCAN = 2.

If your spec sheet gives you the frame period in

units of lines, use this value for VTOT. Here are

some ways to calculate the value for VTOT from

other data on your spec sheet:

• A spec sheet may give you the number of

horizontal active and blanked lines per frame

as two separate numbers. Add the two num-

bers to get VTOT.

• A spec sheet for a non-interlaced display may

give you a vertical rate. The value for VTOT

can be calculated using the following formula:

VTOT = HRAT / Vertical Rate

• A spec sheet for an interlaced display may give

you a field or frame rate. The value for VTOT

can be calculated using one of the following

formulas:

VTOT = HRAT / Frame Rate

VTOT = 2 x (HRAT / Field Rate)

• A spec sheet for an interlaced display may give

you the number of active and blanked lines in

a single field. The value for VTOT can be cal-

culated using the following formula:

VTOT = 2 x (Active Lines + Blanked Lines)

The VSPD parameter sets the number of scan lines

between the last line of active video and the begin-

ning of the vertical sync pulse. Many spec sheets

refer to this parameter as “Vertical Sync Front Porch.”

If your spec sheet gives you the vertical front porch

in units of lines, use this value for VSPD. Here is

another way to calculate the value for HSPD from

other data on your spec sheet:

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Quantum-data 801GC Manual do Utilizador Página 179