Parameters: 

x : 1D array or sequence 
Array or sequence 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. 
mode : {'default', 'psd', 'magnitude', 'angle', 'phase'} 
What sort of spectrum to use. Default is 'psd', which takes the power spectral density. 'magnitude' returns the magnitude spectrum. 'angle' returns the phase spectrum without unwrapping. 'phase' returns the phase spectrum with unwrapping. 
noverlap : int 
The number of points of overlap between blocks. The default value is 128. 
scale : {'default', 'linear', 'dB'} 
The scaling of the values in the spec. 'linear' is no scaling. 'dB' returns the values in dB scale. When mode is 'psd', this is dB power (10 * log10). Otherwise this is dB amplitude (20 * log10). 'default' is 'dB' if mode is 'psd' or 'magnitude' and 'linear' otherwise. This must be 'linear' if mode is 'angle' or 'phase'. 
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.  cmap

A matplotlib.colors.Colormap instance; if None, use default determined by rc 
xextent : None or (xmin, xmax) 
The image extent along the xaxis. The default sets xmin to the left border of the first bin (spectrum column) and xmax to the right border of the last bin. Note that for noverlap>0 the width of the bins is smaller than those of the segments.  **kwargs

Additional kwargs are passed on to imshow which makes the specgram image. 