function log_filename=generate_log_filename(time_since_previous_trial)
%gives filename w/ dwn, date, and time since midnight in ms
%global log_filename
dwn_='dwn_';
in='_in_';
daq='.daq';
elapsed_ms=int2str(time_since_previous_trial);
elapsed_ms=strcat('_sp_',elapsed_ms);
%path='C:\MATLAB6p1\work\dwn_rawdata_2003\';        --storage path was formerly prefixed to log_filename
log_filename=strcat(dwn_,date,in,int2str(timesincemidnightinms(clock)),elapsed_ms,daq);