Parameters: 

x, y : 1D arrays or sequences 
Arrays or sequences containing the data. 
Fs : scalar 
The sampling frequency (samples per time unit). It is used to calculate the Fourier frequencies, freqs, in cycles per time unit. The default value is 2. 
window : callable or ndarray 
A function or a vector of length NFFT. To create window vectors see window_hanning , window_none , numpy.blackman , numpy.hamming , numpy.bartlett , scipy.signal , scipy.signal.get_window , etc. The default is window_hanning . If a function is passed as the argument, it must take a data segment as an argument and return the windowed version of the segment. 
sides : {'default', 'onesided', 'twosided'} 
Specifies which sides of the spectrum to return. Default gives the default behavior, which returns onesided for real data and both for complex data. 'onesided' forces the return of a onesided spectrum, while 'twosided' forces twosided. 
pad_to : int 
The number of points to which the data segment is padded when performing the FFT. This can be different from NFFT, which specifies the number of data points used. While not increasing the actual resolution of the spectrum (the minimum distance between resolvable peaks), this can give more points in the plot, allowing for more detail. This corresponds to the n parameter in the call to fft(). The default is None, which sets pad_to equal to NFFT 
NFFT : int 
The number of data points used in each block for the FFT. A power 2 is most efficient. The default value is 256. This should NOT be used to get zero padding, or the scaling of the result will be incorrect. Use pad_to for this instead. 
detrend : {'none', 'mean', 'linear'} or callable, default 'none' 
The function applied to each segment before ffting, designed to remove the mean or linear trend. Unlike in MATLAB, where the detrend parameter is a vector, in Matplotlib is it a function. The mlab module defines detrend_none , detrend_mean , and detrend_linear , but you can use a custom function as well. You can also use a string to choose one of the functions: 'none' calls detrend_none . 'mean' calls detrend_mean . 'linear' calls detrend_linear . 
scale_by_freq : bool, optional 
Specifies whether the resulting density values should be scaled by the scaling frequency, which gives density in units of Hz^1. This allows for integration over the returned frequency values. The default is True for MATLAB compatibility. 
noverlap : int 
The number of points of overlap between segments. The default value is 0 (no overlap). 
Fc : int 
The center frequency of x (defaults to 0), which offsets the x extents of the plot to reflect the frequency range used when a signal is acquired and then filtered and downsampled to baseband. 
return_line : bool 
Whether to include the line object plotted in the returned values. Default is False. 
Returns: 

Pxy : 1D array 
The values for the cross spectrum P_{xy} before scaling (complex valued). 
freqs : 1D array 
The frequencies corresponding to the elements in Pxy. 
line : a Line2D instance 
The line created by this function. Only returned if return_line is True. 
Other Parameters: 
 **kwargs

Keyword arguments control the Line2D properties:
Property  Description 
agg_filter  a filter function, which takes a (m, n, 3) float array and a dpi value, and returns a (m, n, 3) array 
alpha  float 
animated  bool 
antialiased or aa  bool 
clip_box  Bbox 
clip_on  bool 
clip_path  [(Path , Transform )  Patch  None] 
color or c  color 
contains  callable 
dash_capstyle  {'butt', 'round', 'projecting'} 
dash_joinstyle  {'miter', 'round', 'bevel'} 
dashes  sequence of floats (on/off ink in points) or (None, None) 
drawstyle or ds  {'default', 'steps', 'stepspre', 'stepsmid', 'stepspost'}, default: 'default' 
figure  Figure 
fillstyle  {'full', 'left', 'right', 'bottom', 'top', 'none'} 
gid  str 
in_layout  bool 
label  object 
linestyle or ls  {'', '', '.', ':', '', (offset, onoffseq), ...} 
linewidth or lw  float 
marker  marker style 
markeredgecolor or mec  color 
markeredgewidth or mew  float 
markerfacecolor or mfc  color 
markerfacecoloralt or mfcalt  color 
markersize or ms  float 
markevery  None or int or (int, int) or slice or List[int] or float or (float, float) 
path_effects  AbstractPathEffect 
picker  float or callable[[Artist, Event], Tuple[bool, dict]] 
pickradius  float 
rasterized  bool or None 
sketch_params  (scale: float, length: float, randomness: float) 
snap  bool or None 
solid_capstyle  {'butt', 'round', 'projecting'} 
solid_joinstyle  {'miter', 'round', 'bevel'} 
transform  matplotlib.transforms.Transform 
url  str 
visible  bool 
xdata  1D array 
ydata  1D array 
zorder  float  