dtla.py 文件源码

def get_data(filename, channel=None, start=0, length=None, detrend='linear'):
    """Load selected data from DTLA recording.

    :param filename: name of the datafile
    :param channel: list of channels to read (base 0, None to read all channels)
    :param start: sample index to start from
    :param length: number of samples to read (None means read all available samples)
    :param detrend: processing to be applied to each channel to remove offset/bias
                    (supported values: ``'linear'``, ``'constant'``, ``None``)
    """
    if channel is None:
        channel = range(_channels)
    elif isinstance(channel, int):
        channel = [channel]
    if length is None:
        length = get_data_length(filename)-start
    with open(filename, 'rb') as f:
        f.seek(start*_framelen, _os.SEEK_SET)
        data = _np.fromfile(f, dtype=_np.uint16, count=_framelen/2*length)
    data = _np.reshape(data, [length,_framelen/2])
    data = data[:,2:]
    data = _np.take(data, channel, axis=1).astype(_np.float)
    if len(channel) == 1:
        data = data.ravel()
    data = 5*data/65536-2.5
    if detrend is not None:
        data = _sig.detrend(data, axis=0, type=detrend)
    return data