Ttl Pulse; Pulse Width - Matrox Meteor Installation And Hardware Reference

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TTL signal
external trigger
arrival of
trigger pulse
even field
Video data

TTL pulse

Matrox Meteor/RGB trigger input accepts a TTL level pulse.
The TTL level signal must have a maximum amplitude of 5V.
A signal over 2V is considered high while anything less than
0.8V is considered low. The transition of 0.8V to 2V is considered
to be the rising edge.
The Trigger Control Logic waits for the falling edge of the
signal. Upon the active trigger signal, the Trigger Control Logic
instructs the Digital Video to PCI Interface to send the next
frame to the PCI bus. The beginning of the next video frame is
the falling edge of the even field's vsync. Depending on when
the trigger arrives in relationship to the video signal, the period
between the arrival of the pulse and the frame transfer to the
PCI will be null or a maximum of one full frame
time lapse
odd field

Pulse width

The Trigger Control Logic cannot detect the trigger signal's
edge unless the trigger signal's pulse width is at least greater
than one pixel. You can determine the pulse width by taking
the inverse of the pixel frequency. The pulse width of one pixel
on the Meteor is as follows:
NTSC Pixel Frequency = 12.27 MHz
Pulse Width = 1/ Pixel Frequency
PAL Pixel Frequency = 14.75 MHz
Pulse Width = 1/ Pixel Frequency
Using the Matrox Meteor trigger
start of grab is the beginning
of next even field
even field
∴
≈
82 nanoseconds
∴
≈
68 nanoseconds
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