morse code to wavefile implemented in python

morse_str_to_wav.py

def morse_code_to_wav(morse_str, sr=8000, short_burst_len=0.1, long_burst_len=0.2,
                      pause_len=0.05, frequency=500, output_file_name=None):
    """
    @param morse_str: str containing . for short burst - for long burst and space for pause between words
    @param sr: sampling frequency of the desired wav output
    @param output_file_name: path to wavfile output
    """
    amplitude = np.iinfo(np.int16).max * 0.7
    t_pause = np.linspace(0, pause_len, int(sr * pause_len))
    t_pause[:] = 0
    sig = np.empty(0, dtype=np.int16)
    for c in morse_str:
        if c == '.':
            t = np.linspace(0, short_burst, int(sr * short_burst_len))
            morse_sig = amplitude * np.sin(2. * np.pi * frequency * t)
            sig = np.append(sig, np.append(morse_sig, t_pause))
        if c == '-':
            t = np.linspace(0, long_burst, int(sr * long_burst_len))
            morse_sig = amplitude * np.sin(2. * np.pi * frequency * t)
            sig = np.append(sig, np.append(morse_sig, t_pause))
        if c == ' ':
            t = np.linspace(0, long_burst, int(sr * long_burst_len))
            t[:] = 0
            morse_sig = np.append(morse_sig, t)
    if output_file_name is not None:
        wavfile.write(output_file_name, sr, sig.astype(np.int16))