Changes between Version 4 and Version 5 of Sensors/Specim

Timestamp:

Dec 14, 2009, 11:10:31 AM (15 years ago)

Author:

mggr

Comment:

--

Sensors/Specim

@@ -21 +21 @@
 The data from the CCD is transferred to a framegrabber card in the computer using [http://en.wikipedia.org/wiki/Camera_Link Camera Link].  As this is a digital protocol, there are no digitisation effects to worry about.
 
-The frame grabber lag time is apparently 55ms regardless of frame rate (i.e. a frame is captured 55ms after the nav sync pulse).
+== Timing ==
+
+Both Specim instruments are connected to a nav-sync box that timestamps the start of acquisition against GPS time.  This measures the time from the start of acquisition pulse to the next GPS pulse-per-second.
+
+The frame grabber lag time is apparently 55ms regardless of frame rate (i.e. a frame is captured 55ms before the nav sync pulse).
+
+Consequently the timing of a start of acquisition is `next_GPS_PPS - navsync_time - 55ms`. [mggr: check this isn't +55ms!]
 
 == Eagle ==