#! /usr/bin/env python
# -*- coding: utf-8 -*-
# vim:fenc=utf-8
#
# Copyright © 2015 jaidev <jaidev@newton>
#
# Distributed under terms of the MIT license.

"""
=========================================================
Wigner-Ville Distribution of Chirps with Different Slopes
=========================================================

This example demonstrates the Wigner-Ville distribution of a signal
composed of two chirps with Gaussian amplitude modulation but havind linear
frequency modulations with different slopes. Note that the AF interference
terms are located away from the origin. We can see the two distint signal
terms, but there is some interference around the middle.

Figure 4.12 from the tutorial.
"""

from tftb.generators import fmlin, amgauss
from tftb.processing import WignerVilleDistribution
import numpy as np

n_points = 64
sig1 = fmlin(n_points, 0.2, 0.5)[0] * amgauss(n_points)
sig2 = fmlin(n_points, 0.3, 0)[0] * amgauss(n_points)
sig = np.hstack((sig1, sig2))

tfr = WignerVilleDistribution(sig)
tfr.run()
tfr.plot(kind='contour', show_tf=True)