Log entry time 02:59:12 on June 8,2004

Entry number 124937

Used run 1960 to check the synchronization of all of the crates in the HAPPEX DAQ.  

First, an explanation..
   A frequency between 0.6 and 2.0Mhz is choosen at random at the beginning of a helicity window.  During part of this window, this frequency is sent as "SYNC1" to the counting house, right arm, left arm.  The other part of the window defines "SYNC2"... which is also sent to those crates.  "SYNC0" which is only sent to the counting house crate, should therefore be the sum of "SYNC1" and "SYNC2".

First plot: Sync SumCheck plots
    Checks for the above mentioned sum.... actually checks for zero (i.e. SYNC1+SYNC2-SYNC0).  All crates show a zero within the bit resolution of the scalers.

Second plot:  Sync Differences
    Shows SYNCs with respect to eachother... another zero check (e.g. LSYNC1-CHSYNC1 =? 0).  All appear to be zero, within the bit resolution of the scalers.   Interesting enough... the bit noise seems to suggest that the spectrometers appear lag a bit behind the counting house crate (which may be caused by intermediate electronic modules used to convert BNC to ECL).  The difference between the left and the Right arm may also show the difference in cable lengths from the Counting house to each spectrometer arm (the transmission time has been measured in both... and they're different by 30ns... which is about 1/3 the size of a frequency pulse).