Source code for tesfdmtools.methods.IQrotate

#!/usr/bin/env python3
'''
.. module:: IQrotate
   :synopsis: Rotate I/Q signals of TES pulse  
.. moduleauthor:: Cor de Vries <c.p.de.vries@sron.nl>

'''

import numpy

e=numpy.exp(1.0)                                # define e

[docs]def IQrotate(Isig,Qsig):
   '''
   Rotate I and Q signals of TES pulse to get an average angle of zero

   Args:
      * `Isig` = record with I-signal
      * `Qsig` = record with Q-signal
  
   Returns:
      * `Isig` = record with rotated I-signal 
      * `Qsig` = record with rotated Q-signal

   '''

   a,b=numpy.polyfit(Isig,Qsig,1)               # fit y=a*x + b

   phase=numpy.arctan(a)                        # get phase (radians)

   cc=(Isig+1j*Qsig)*e**(1j*phase)              # make rotated complex signal

   Inew=numpy.real(cc)
   Qnew=numpy.imag(cc)

   Inew=Inew-(Inew[0]-Isig[0])
   Qnew=Qnew-(Qnew[0]-Qsig[0])

   return (Inew,Qnew)

   
[docs]def IQphase(Isig,Qsig):
   '''
   Get average angle of TES pulse in I/Q plane 

   Args:
      * `Isig` = record with I-signal
      * `Qsig` = record with Q-signal
  
   Returns:
      * 'angle` = angle (radians)

   '''

#   a,b=numpy.polyfit(Isig,Qsig,1)                # fit y=a*x + b

   ai=(float(Isig.max())+float(Isig.min()))/2.0
   aq=(float(Qsig.max())+float(Qsig.min()))/2.0

   return numpy.arctan2(aq,ai)                    # return phase


[docs]def IQphrot(Isig,Qsig,phase):
   '''
   Rotate I and Q signals of TES pulse with given angle

   Args:
      *  `Isig` = record with I-signal
      *  `Qsig` = record with Q-signal
      * `phase` = phase to be rotated (radians)
  
   Returns:
      * `Isig` = record with rotated I-signal 
      * `Qsig` = record with rotated Q-signal

   '''

   cc=(Isig+1j*Qsig)*e**(1j*phase)                # make rotated complex signal

   Inew=numpy.real(cc)
   Qnew=numpy.imag(cc)

#   Inew=Inew-(Inew[0]-Isig[0])
#   Qnew=Qnew-(Qnew[0]-Qsig[0])

   return (Inew,Qnew)