dpsk

from __future__ import division

from numpy import ones,arange,cos,sin,pi

import numpy as np

from matplotlib.pyplot import plot,subplot,title,xlabel,ylabel,show,legend,grid,subplot

Fs =150.0;  # sampling rate

Ts = 1.0/Fs; # sampling interval

freq=10

t = np.arange(0,2,Ts)

bk = [1,0,0,1,0,0,1,1]##input digital sequence

bk_not=[]

for i in range(0,len(bk)):

  if(bk[i]==1):

   bk_not.append(0)

  else:

    bk_not.append(1)

dk_1 = [ 1 and bk[0]]#  #initial value of differential encoded sequence

dk_1_not =[ 0 and bk_not[0]]

dk = [dk_1[0]^dk_1_not[0]] #first bit of dpsk encoder

for i in range(1,len(bk)):

  dk_1.append(dk[(i-1)])

  if dk[(i-1)]==1:

     x=0

  else:

    x=1

  dk_1_not.append(x)

  dk.append(((dk_1[i] and bk[i])^(dk_1_not[i] and bk_not[i])))

dk_radians=[]

for i in range(0,len(dk)):

  if(dk[i]==1):

    dk_radians.append(0)

  elif(dk[i]==0):

    dk_radians.append(180)

print ('Table 7.3 Illustrating the Generation of DPSK Signal')

print ('_____________________________________________________')

print ('\n(bk)',bk)

print ('\n(bk_not)',bk_not)

print ('\nDifferentially encoded sequence (dk)')

for dd in dk:

    print (dd,'\t')

print ('\n\nTransmitted phase in radians')

for ddd in dk_radians:

    print (ddd,'\t')

print ('\n\n_____________________________________________________')

bit_arr =np.array([0,180,0,0,180])

samples_per_bit = 2*Fs/bit_arr.size

dd = np.repeat(bit_arr, samples_per_bit)

y= np.sin(2 * np.pi * (freq) * t+(np.pi*dd/180))

plot(t,y)

show()