Hi All, Just a small point on this matter. Most FCS files generated by the commercial machines use channel values from 0-1023, whereas the range is 1024 channels. If you are writing an algorithm and are just going to plug the channel value into the formula below you will get 9908 for channel 1023, which will be the maximum value in the file. So, you might want to make R=1023 or add 1 to all the channel values, that way you are correct at the upper end. Since the scale is degenerate at the lower end the error there shouldn't be noticeable. Making this correction or not shouldn't make much of a difference as long as you are consistent when analyzing all your data. -Dave At 10:55 AM 6/30/99 -0700, Mario Roederer wrote: > >Scale (linear) Value = f * 10^ [(C * n) / R] > >where > >C = channel number >n = number of decades for the full range (~4 on BD & Cytomation machines, >~3 on many Coulters) >R = range (maximum number of channels; typically 1024) >f = log offset (typically 1 or 0.1) > >The FCS keyword $PxE (x = parameter number) has the values for f and n >(e.g., <$P4E = 4,0.1> means that parameter 4 has a 4 decade range with the >linear scale value of channel 0 equal to 0.1); $PxR has the value for R. >Note that for most BD-generated FCS files, the offset for all log >parameters is incorrectly stored in the FCS keyword list as 0 (zero); it >should be 1.0. > >mr >
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