filter_allan

filter_allan takes data on standard input and generates Allan plots and related statistics for a filter based absorption instrument zero run. This is used to analyze the noise characteristics of the instrument with respect to the averaging time employed.

The output consists of a report on standard output containing the result of fitting the lines in the Allan plots and the measured noise at selected averaging intervals. Additionally four plots are generated:

• Allan_Arithmetic.png - The Allan plot for arithmetic (non-difference) averages of attenuation coefficients.
• Allan_Difference.png - The Allan plot for difference measurement attenuation coefficients.
• Attenuation_FrequencyDomain.png - The frequency domain power spectrum of the attenuation data.
• Attenuation_TimeDomain.png - The time domain (time series) of the attenuation data.

data ... | data.export --mode=r | filter_allan [instrument]
               

The instrument code used to disambiguate the data generated. Normally not required when only dealing with output that contains only a single instrument. This can also be set to “simulation” to generate simulated plots.

data.get sfd A14a 2015-07-21T01:24:09Z 2015-07-21T09:24:09Z | da.export --mode=r | filter_allan > results.csv