Beckman Coulter Navios, Instructions For Use Manual

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773232AH
3-16
Operation Principles
Plot Display
Log-Log Mean Method
Weighting each channel according to its face value as given by the log scale performs this
calculation of Mean.
Example
When using a four-decade uncalibrated logarithmic display reporting output as Channels, you
might give channel zero (the lowest channel) a value 10
-1
= 0.1 and on a 1024 channel display,
channel 1023 is given the value 10
-3
= 1000. All raw digital channel values are converted to an
absolute value (Relative Channel Number) in the range 0.1 to 1000 before calculations are performed
for the mean.
The mean can then be reported in Channel numbers in the range 0 to 1023 thus:
Where:
C
n
= Raw digital channel number
C
ch
= Channel count
C
d
= Channels per decade
N = Integral of all counts between & including marker channels
= Mean channel number (rounded to nearest whole channel)
For Calibrated values, the calculation is reported as the calibrated value in the range Log Offset to
The log offset cannot be zero since a log offset of zero is 10 (minus infinity), which is not possible to
represent on paper or on screen. Navios software does not allow log offset values of less than 0.1.
Numbers entered in the logarithmic offset are clamped at 0.1 if a number less than this is entered.
Lin-Log Mean Method
This method of Mean calculation is worked out by performing a simple arithmetic mean channel
calculation on raw data according to its channel value in the range 0 to 1023 (for 1024 channel data).
The Mean value can then be reported as channels (in the range 0 to 1023) or converted to the
Relative Channel value.
Using the same data as in the previous example…
Lin-Log Mean method reported in Channel numbers in the range 0-1023 thus: