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Gijs Molenaar edited this page Feb 13, 2014 · 5 revisions

PolcLog

The PolcLog is an extension to Polc. Instead of a polynomial with n x m coefficients :

  • v(f,t) = c00 + c01t + c10f + c11f t + c02t2 + c20f2 + .... it replaces f, t with -> 10log(f/l0) , 10log(t/l0).

To create a PolcLog from glish call:

my_logpolc:=meq.polc(my_array,class='MeqPolcLog');

Per default the transformation is applied both on the frequency and time axis (and no other axis) and l0 = 1. The user can define its own set of axes and scales by defining the record axis_list, eg.:

my_logpolc.axis_list = {freq=3.}

or:

my_logpolc.axis_list = {freq=3.,time=0}

will leave time unchanged and use l0=3 for frequency.

The scales are stored in the ParmTable in the column 'LScale', at the moment only time/freq is supported.

This class can be used as an example class to define other functions on the axis.

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