[tsaksa]

Your post says the counts are taken over 100ms intervals. But in reality the samples will not be taken over exact or equal time intervals due to differences in program execution and timing. Particularly if you are running a virtual machine. You need to read the real time clock to know the real length of each sample interval. Are you getting the real time when each sample is made and then dividing the counts by the real time to get a number proportional to velocity?