Fix frequency channels for high frequency #45
Description
Original report by kevin_karplus (Bitbucket: kevin_karplus, ).
To the frequency f, add f_s min(0, tau f - 1), where f_s is the sampling frequency and tau is the dead time for resetting the DMA counter.
Still need to determine the (board-specific) dead time, but 900ns looks about right from the measurements of error in the frequency channels that I made today.