Module « scipy.signal »

Fonction lp2hp - module scipy.signal

Signature de la fonction lp2hp

def lp2hp(b, a, wo=1.0) 

Description

lp2hp.__doc__

    Transform a lowpass filter prototype to a highpass filter.

    Return an analog high-pass filter with cutoff frequency `wo`
    from an analog low-pass filter prototype with unity cutoff frequency, in
    transfer function ('ba') representation.

    Parameters
    ----------
    b : array_like
        Numerator polynomial coefficients.
    a : array_like
        Denominator polynomial coefficients.
    wo : float
        Desired cutoff, as angular frequency (e.g., rad/s).
        Defaults to no change.

    Returns
    -------
    b : array_like
        Numerator polynomial coefficients of the transformed high-pass filter.
    a : array_like
        Denominator polynomial coefficients of the transformed high-pass filter.

    See Also
    --------
    lp2lp, lp2bp, lp2bs, bilinear
    lp2hp_zpk

    Notes
    -----
    This is derived from the s-plane substitution

    .. math:: s \rightarrow \frac{\omega_0}{s}

    This maintains symmetry of the lowpass and highpass responses on a
    logarithmic scale.

    Examples
    --------
    >>> from scipy import signal
    >>> import matplotlib.pyplot as plt

    >>> lp = signal.lti([1.0], [1.0, 1.0])
    >>> hp = signal.lti(*signal.lp2hp(lp.num, lp.den))
    >>> w, mag_lp, p_lp = lp.bode()
    >>> w, mag_hp, p_hp = hp.bode(w)

    >>> plt.plot(w, mag_lp, label='Lowpass')
    >>> plt.plot(w, mag_hp, label='Highpass')
    >>> plt.semilogx()
    >>> plt.grid()
    >>> plt.xlabel('Frequency [rad/s]')
    >>> plt.ylabel('Magnitude [dB]')
    >>> plt.legend()