import matplotlib.pyplot as plt
import numpy as np
import scipy.signal as signal



def plot_spectrogram(data,NFFT,Fs,ex ):
    plt.specgram(data, NFFT=NFFT, Fs=Fs)
    plt.title("Spectrogram of data")
    plt.ylim(-Fs/2, Fs/2)
    plt.show()
    plt.close()

    if ex:
        exit()


###  Parameters
F_offset = 250000
Fs = 1140000

###  Generate a digital complex exponential with phase -F_offset/Fs
fc1 = np.exp(-1.0j*2.0*np.pi* F_offset/Fs*np.arange(len(x1)) )
plot_spectrogram(fc1, 512, Fs,ex=True)

plt.plot(20*np.log10(np.abs(np.fft.fft(fc1[:512]*np.hanning(512)))))