# obspy.signal.invsim.cosine_taper

cosine_taper(npts, p=0.1, freqs=None, flimit=None, halfcosine=True, sactaper=False)[source]

Cosine Taper.

Parameters:
• npts (int) – Number of points of cosine taper.

• p (float) – Decimal percentage of cosine taper (ranging from 0 to 1). Default is 0.1 (10%) which tapers 5% from the beginning and 5% form the end.

• freqs (NumPy `ndarray`) – Frequencies as, for example, returned by fftfreq

• flimit (list(float, float, float, float) or tuple(float, float, float, float)) – The list or tuple defines the four corner frequencies (f1, f2, f3, f4) of the cosine taper which is one between f2 and f3 and tapers to zero for f1 < f < f2 and f3 < f < f4.

• halfcosine (bool) – If True the taper is a half cosine function. If False it is a quarter cosine function.

• sactaper (bool) – If set to True the cosine taper already tapers at the corner frequency (SAC behavior). By default, the taper has a value of 1.0 at the corner frequencies.

Return type:

float NumPy `ndarray`

Returns:

Cosine taper array/vector of length npts.

Example

```>>> tap = cosine_taper(100, 1.0)
>>> tap2 = 0.5 * (1 + np.cos(np.linspace(np.pi, 2 * np.pi, 50)))
>>> np.allclose(tap[0:50], tap2)
True
>>> npts = 100
>>> p = 0.1
>>> tap3 = cosine_taper(npts, p)
>>> (tap3[int(npts*p/2):int(npts*(1-p/2))]==np.ones(int(npts*(1-p)))).all()
True
```