Sends a pulse train of on-off in Dev1/port0/line24.

    This function creates a task, starts it and waits until it is over.
    Uses expt_settings.external_clock_line as a clock.

    n_samples - number of on off samples.

def p24_pulse_train(n_samples=100):
    """Sends a pulse train of on-off in Dev1/port0/line24.

    This function creates a task, starts it and waits until it is over.
    Uses expt_settings.external_clock_line as a clock.

    n_samples - number of on off samples.
    """
    samples = (np.arange(n_samples, dtype="uint32") % 2)*(2**24)
    samples[-1] = 0
    DigitalOutputTask("Dev1/port0/line24", samples).StartAndWait()