BNC 1420 - Video Microscope - Manual (Page 29)

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Camera A/D
converter
RAM buffer
Video display
Hard disk
Buffering scheme in scopePRO
The analog video signal from the Model 1420 camera is digitized in the
Hauppauge WinTV card into an 8 bit data stream. This stream is
continually stored in a cyclic RAM buffer in PC memory, such that the
most recent video data is always residing in RAM. As soon as a trigger or
keyboard action stops the recording, you freeze the video sequence in the
RAM buffer, which contains the video of the events prior to the trigger.
This sequence can subsequently be stored on disk.
The duration of the video sequence depends on the amount RAM, set
aside for the buffer. The more RAM installed in the computer, the more
buffer space can be set aside without slowing down other tasks. The initial
buffer size is set to half the available RAM, but you may want to adjust
the buffer size get longer pre-trigger video sequence duration. Buffer size
is specified in The View>Video options>Buffer settings menu.