:orphan:

spectrum3
---------


Sample microphone input and display spectrogram


.. code-block:: python
    
    
    
    import pyaudio
    import numpy as np
    import time
    import gr
    import gr3
    
    FS = 44100  # Sampling frequency
    SAMPLES = 1024
    
    mic = None
    
    
    def get_spectrum():
        global mic
        if mic is None:
            pa = pyaudio.PyAudio()
            mic = pa.open(format=pyaudio.paInt16, channels=1, rate=FS,
                          input=True, frames_per_buffer=SAMPLES)
        amplitudes = np.frombuffer(mic.read(SAMPLES), dtype=np.short)
        return abs(np.fft.fft(amplitudes / 32768.0))[:SAMPLES // 2]
    
    
    spectrum = np.zeros((256, 256), dtype=float)
    t = -255
    dt = float(SAMPLES) / FS
    df = FS / float(SAMPLES) / 2 / 2
    
    start = time.time()
    
    while time.time() - start < 10:
        try:
            power = get_spectrum()
        except (IOError):
            continue
    
        gr.clearws()
        spectrum[:, 255] = power[:256]
        spectrum = np.roll(spectrum, 1)
        gr.setcolormap(-113)
        gr.setviewport(0.05, 0.95, 0.1, 1)
        gr.setwindow(t * dt, (t + 255) * dt, 0, df)
        gr.setscale(gr.OPTION_FLIP_X)
        gr.setspace(0, 200, 30, 80)
        gr3.surface((t + np.arange(256)) * dt, np.linspace(0, df, 256), spectrum, 4)
        gr.setscale(0)
        gr.axes3d(0.2, 0.2, 0, (t + 255) * dt, 0, 0, 5, 5, 0, -0.01)
        gr.titles3d('t [s]', 'f [kHz]', '')
        gr.updatews()
    
        t += 1