Vertical Synchronization Question

[bishop59]

We have used RTSI synchronization between IMAQ and DAQ to be able to perform a data acquisition every time the camera begins a field using a vertical synchronization signal. Because of processing and display limitations, and because our camera is interlaced, we are only considering the odd field (by using MAX to set the framegrabber to acquire odd fields only). My question is, if we are not acquiring the even field, will the VSYNC signal corresponding to the even field be read by the framegrabber, and still trigger a data acquisition?

Thanks for the help,
John

[nestor-sg]

John,

The framegrabber will route all the VSYNC pulses coming into the board. When you configure a Trigger Drive with VSYNC chosen as the signal, all your VSYNC pulses available in the video signal will be routed. In this case, even when you select field mode acquisition the board is still receiving the whole image (two fields) from the camera, it later ignores one of the field for the purpose of building the image and sending it to memory, but in the hardware level the 60 Hz VSYNC signal is still coming, 60 Hz if we are talking about a 30fps standard camera (i.e. RS-170).

Hope this helps.

Nestor S.