From: Borries Demeler <demeler@bioc02.uthscsa.edu>
  To  : rasmb@bbri.harvard.edu
  Date: Tue, 10 Dec 1996 06:59:55 -0600 (CST)

Re: spikes in xla data.

> hey all!
> 
> Does anyone else see occasionaly random spikes in the their sedV scans 
> on the xla?  This is nothing systematic, they just appear from time to 
> time...   I put this down to just random noise or an instrumental 
> glitch, but Tim (Lohman) wanted me to check just to make sure..
> 
> Thanks.
> razmic
> 
The spikes are caused by misfirings in the lamp, and I am not quite certain
wether it is really a truly random event, does it happen with the same 
frequency regardless of speed? 

We have 2 XL-A's and we used to see it a lot more on one than the other, 
until some hardware was replaced, suggesting that something can be done 
about it.

On one machine we see about 1 spike/300 scans, on the other it is more like 
1 out of 50. But I haven't checked this out systematically.

The UltraScan software package comes with a utility to graphically edit
out spikes (or window scratches) from data, using the mouse.

Regards, -Borries