153f77827dd75fc74aff90838d0f6b3955c1b27d,sk_dsp_comm/digitalcom.py,,QAM_SEP,#Any#Any#Any#Any#Any#Any#,423

Before Change

    rx_data = np.rint((M-1)*(rx_data + (1+1j))/2.)
    // Fix-up edge points real part
    s1r = mlab.find(rx_data.real > M - 1)
    s2r = mlab.find(rx_data.real < 0)
    rx_data.real[s1r] = (M - 1)*np.ones(len(s1r))
    rx_data.real[s2r] = np.zeros(len(s2r))
    // Fix-up edge points imag part
    s1i = mlab.find(rx_data.imag > M - 1)
    s2i = mlab.find(rx_data.imag < 0)
    rx_data.imag[s1i] = (M - 1)*np.ones(len(s1i))
    rx_data.imag[s2i] = np.zeros(len(s2i))
    rx_data = 2*rx_data - (M - 1)*(1 + 1j)
    //Correlate the first Ncorr symbols at four possible phase rotations
    R0,lags = xcorr(rx_data,tx_data,Ncorr)
    R1,lags = xcorr(rx_data*(1j)**1,tx_data,Ncorr) 
    R2,lags = xcorr(rx_data*(1j)**2,tx_data,Ncorr) 
    R3,lags = xcorr(rx_data*(1j)**3,tx_data,Ncorr) 
    //Place the zero lag value in the center of the array
    R0max = np.max(R0.real)
    R1max = np.max(R1.real)
    R2max = np.max(R2.real)
    R3max = np.max(R3.real)
    R = np.array([R0max,R1max,R2max,R3max])
    Rmax = np.max(R)
    kphase_max = np.where(R == Rmax)[0]
    kmax = kphase_max[0]
    //Find correlation lag value is zero at the center of the array
    if kmax == 0:
        lagmax = lags[np.where(R0.real == Rmax)[0]]
    elif kmax == 1:
        lagmax = lags[np.where(R1.real == Rmax)[0]]
    elif kmax == 2:
        lagmax = lags[np.where(R2.real == Rmax)[0]]
    elif kmax == 3:
        lagmax = lags[np.where(R3.real == Rmax)[0]]
    taumax = lagmax[0]
    if SEP_disp:
        print("Phase ambiquity = (1j)**%d, taumax = %d" % (kmax, taumax))
    //Count symbol errors over the entire input ndarrays
    //Begin by making tx and rx length equal and apply 
    //phase rotation to rx_data
    if taumax < 0:
        tx_data = tx_data[-taumax:]
        tx_data = tx_data[:min(len(tx_data),len(rx_data))]
        rx_data = (1j)**kmax*rx_data[:len(tx_data)]
    else:
        rx_data = (1j)**kmax*rx_data[taumax:]
        rx_data = rx_data[:min(len(tx_data),len(rx_data))]
        tx_data = tx_data[:len(rx_data)]
    //Convert QAM symbol difference to symbol errors
    errors = np.int16(abs(rx_data-tx_data))
    // Detect symbols errors
    // Could decode bit errors from symbol index difference
    idx = mlab.find(errors != 0)
    if SEP_disp:
        print("Symbols = %d, Errors %d, SEP = %1.2e" \
               % (len(errors), len(idx), len(idx)/float(len(errors))))
    return  len(errors), len(idx), len(idx)/float(len(errors))

After Change

    rx_data = np.rint((M-1)*(rx_data + (1+1j))/2.)
    // Fix-up edge points real part
    s1r = np.nonzero(np.ravel(rx_data.real > M - 1))[0]
    s2r = np.nonzero(np.ravel(rx_data.real < 0))[0]
    rx_data.real[s1r] = (M - 1)*np.ones(len(s1r))
    rx_data.real[s2r] = np.zeros(len(s2r))
    // Fix-up edge points imag part
    s1i = np.nonzero(np.ravel(rx_data.imag > M - 1))[0]
    s2i = np.nonzero(np.ravel(rx_data.imag < 0))[0]
    rx_data.imag[s1i] = (M - 1)*np.ones(len(s1i))
    rx_data.imag[s2i] = np.zeros(len(s2i))
    rx_data = 2*rx_data - (M - 1)*(1 + 1j)
    //Correlate the first Ncorr symbols at four possible phase rotations
    R0,lags = xcorr(rx_data,tx_data,Ncorr)
    R1,lags = xcorr(rx_data*(1j)**1,tx_data,Ncorr) 
    R2,lags = xcorr(rx_data*(1j)**2,tx_data,Ncorr) 
    R3,lags = xcorr(rx_data*(1j)**3,tx_data,Ncorr) 
    //Place the zero lag value in the center of the array
    R0max = np.max(R0.real)
    R1max = np.max(R1.real)
    R2max = np.max(R2.real)
    R3max = np.max(R3.real)
    R = np.array([R0max,R1max,R2max,R3max])
    Rmax = np.max(R)
    kphase_max = np.where(R == Rmax)[0]
    kmax = kphase_max[0]
    //Find correlation lag value is zero at the center of the array
    if kmax == 0:
        lagmax = lags[np.where(R0.real == Rmax)[0]]
    elif kmax == 1:
        lagmax = lags[np.where(R1.real == Rmax)[0]]
    elif kmax == 2:
        lagmax = lags[np.where(R2.real == Rmax)[0]]
    elif kmax == 3:
        lagmax = lags[np.where(R3.real == Rmax)[0]]
    taumax = lagmax[0]
    if SEP_disp:
        print("Phase ambiquity = (1j)**%d, taumax = %d" % (kmax, taumax))
    //Count symbol errors over the entire input ndarrays
    //Begin by making tx and rx length equal and apply 
    //phase rotation to rx_data
    if taumax < 0:
        tx_data = tx_data[-taumax:]
        tx_data = tx_data[:min(len(tx_data),len(rx_data))]
        rx_data = (1j)**kmax*rx_data[:len(tx_data)]
    else:
        rx_data = (1j)**kmax*rx_data[taumax:]
        rx_data = rx_data[:min(len(tx_data),len(rx_data))]
        tx_data = tx_data[:len(rx_data)]
    //Convert QAM symbol difference to symbol errors
    errors = np.int16(abs(rx_data-tx_data))
    // Detect symbols errors
    // Could decode bit errors from symbol index difference
    idx = np.nonzero(np.ravel(errors != 0))[0]
    if SEP_disp:
        print("Symbols = %d, Errors %d, SEP = %1.2e" \
               % (len(errors), len(idx), len(idx)/float(len(errors))))
    return  len(errors), len(idx), len(idx)/float(len(errors))

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