Estimate the Instantaneous Freuqncy of a Chirp

Construct a chirp and estimate its instantaneous frequency.

Figure 2.3 from the tutorial.

from tftb.generators import fmlin
from tftb.processing import plotifl, inst_freq
# TODO: There doesn't have to be something called `plotifl`. Put this into a
# separate visualization module.
import numpy as np


signal, _ = fmlin(256)
time_samples = np.arange(3, 257)
ifr = inst_freq(signal)[0]
plotifl(time_samples, ifr)