Python:DNA melting data analysis

I'm working on this. It is way not finished.

import numpy
import scipy
import scipy.signal as sig
import matplotlib.pyplot as plt
from math import pi

def loadData(expt):
    """
    Loads a raw data file into python. The data file is actually not a
    Matlab .m file, just two columns of numbers. (First column is RTD voltages
    and second column is fluorescence signal voltages.)
    """
    f = open(expt.filename)
    rtdList = []
    fluorList = []
    for line in f:
        rtd, fluor = line.split()
        rtdList.append(rtd)
        fluorList.append(fluor)
    expt.vRTD = numpy.array(rtdList)
    expt.fluorSignal = numpy.array(fluorList)
    f.close()

def plotFilter(f):
    """
    Takes a filter designed with scipy.signal.firwin() and plots
    its frequency response. This is more complicated in Python than in
    Matlab because you have to tell scipy and matplotlib how to talk to each
    other--it's not integrated like in matlab--but it works the same.
    """
    # BUT WHY IS THE MAGNITUDE DIFFERENT
    # I AM CONFUSED
    
    w, h = sig.freqz(f)
    w = w / pi # normalize frequency
    fig = plt.figure()
    plt.title("Digital filter frequency response")
    ax1 = fig.add_subplot(111)
    plt.semilogy(w, numpy.abs(h), 'b')
    plt.xlabel("Normalized frequency (* pi rad/sample)")
    plt.ylabel("Amplitude (dB)", color='b')
    plt.grid()
    ax2=ax1.twinx()
    angles = numpy.unwrap(numpy.angle(h))
    plt.plot(w, angles, 'g')
    plt.ylabel("Angle (rad)", color='g')
    plt.show()

def convertVoltages(expt):
    """
    Accepts an Experiment object with RTD and Fluor voltages and converts them
    to temperature and relative fluorescence values.
    """
    # Convert RTD voltage to temperature.
    # V_rtd = 15 * R_rtd/(R + R_rtd)
    # --> R_rtd = R * (V_rtd - 15)/15
    #
    # R_rtd = 1000 + 3.85(T-273)
    # --> T = 273 + (R_rtd - 1000)/3.85

    expt.rRTD = expt.rOther * (expt.vRTD - 15.0) / 15.0
    expt.temp = 273.15 + (expt.rRTD - 1000.0)/3.85

    # Convert fluorescence signal voltage to relative fluorescence value.
    # (relative fluorescence is the same as dsDNA fraction)

    # Normalize to be between 1 and 0 after denoising
    # NOT FINISHED