functions in filter.i - t

    to_db(signal, ref)  
 or to_db(signal)  


return 20.*log10(abs(SIGNAL)/REF), the number of decibels  
corresponding to the input SIGNAL.  REF defaults to 1.0.  
Interpreted function, defined at i/filter.i   line 510  

    to_phase(signal)  
 or to_phase(signal, 1)  


return atan(SIGNAL.im,SIGNAL.re), the phase of the input SIGNAL.  
If the second argument is present and non-0, the phase will be in  
degrees; by default the phase is in radians.  
To_phase attempts to unroll any jumps from -180 to +180 degrees  
or vice-versa; zero phase will be taken somewhere near the middle  
of the signal.  The external variable to_phase_eps controls the  
details of this unrolling; you can turn off unrolling by setting  
to_phase_eps=0.0 (initially it is 0.3).  
Interpreted function, defined at i/filter.i   line 524