Quadra User's Guide

COMMAND LINE INTERFACE
Timing Parameters
350-7951 Quadra User’s Guide 78
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TIMING PARAMETERS
The table below lists timing parameters, values and ranges used for both the
input and output timing functions. Advanced users can also use the table to
assist with values listed in the “Factory Timing List
.”
For example, if you type INT <input #> to query the system’s Input Timing
values, you will get a string of values (<hfp> <hs> <hbp> <hact> <vfp> <vs>
<vbp> <vact>) that represent Quadra’s settings for that input. The table below
will greatly assist in clarifying each value’s meaning.
Note Internally, Quadra maintains two separate lists of timing
parameters — one for inputs and one for output timings.
However, the parameter definitions and ranges are identical
for both lists.
Table 4-16.
Definitions and Ranges for Timing Parameters
Parameter Definitions Ranges Comments
HFP Horizontal front porch 0 to 640 pixels The beginning of the horizontal
blanking interval.
HS Horizontal sync 16 to 640 pixels The width of the horizontal
synchronizing pulse
HBP Horizontal back porch 0 to 640 pixels The end of the horizontal
blanking interval. The total
horizontal blanking = HFP +
HS + HBP.
HACT Horizontal active 16 to 1920 pixels The active picture interval (non-
blanked portion of the image).
The total pixel count per line =
HACT + HFP + HS + HBP.
VFP Vertical front porch 0 to 512 lines The part of vertical blanking
prior to the vertical sync.
VS Vertical sync 2 to 32 lines The width of the vertical sync
period.
VBP Vertical back porch 0 to 512 lines The part of the vertical blanking
signal following the vertical
sync interval.
VACT Vertical active 12 to 1440 lines The number of active lines of
picture.
VTOT Total Vertical line count NA This parameter is measured by
Quadra. Users may not define
this value, but the sum of VFP +
VS + VACT must equal VTOT.
HFREQ Horizontal frequency in
Hz
12.5 to 125 kHz This parameter is measured by
Quadra. This is a read only
parameter.