Instantaneous Frequency Tracking

In [1]:

    

using PyPlot
import DSP


    

In [2]:

    

include("../juwvid.jl")


    

    
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juwvid

In [3]:

    

# multicomponent data (Boashash+15,p346,Example 6.2.2)
nsample=1024
t,x=sampledata.genmultifm622(nsample);
PyPlot.plot(t,x)
PyPlot.xlabel("t")
PyPlot.ylabel("y")


    

    













    
Out[3]:





PyObject Text(24,0.5,'y')

In [4]:

    

# S-method (constant Lp=6)
sm1=smethod.tfrsm(x,NaN,6,NaN,4);


    

    




Single S-method
Use fft.

In [5]:

    

# initial guess: (t,f) = (-1,80), end point: t=1, window width of df=5.0 
tx,fx=iftrack.track_mode(sm1,t,-1.0,80.0,1.0,5.0)
# initial guess: (t,f) = (-0.2,70), end point: t=0.2, window width of df=5.0
txx,fxx=iftrack.track_mode(sm1,t,-0.2,70.0,0.2,5.0);


    

    




Assuming nft = nsample.
Assuming nft = nsample.
Assuming nft = nsample.
Assuming nft = nsample.
Assuming nft = nsample.
Assuming nft = nsample.

In [7]:

    

fig=PyPlot.figure()
ax = fig[:add_subplot](1,1,1)
a=juwplot.wtfrshow(abs.(sm1),t[2]-t[1],t[1],t[end],NaN,NaN,0.7*2,"gist_gray")
PyPlot.plot(tx,fx,"*",color="C3",lw=2)
PyPlot.plot(txx,fxx,"+",color="C1",lw=2)
PyPlot.title("S-method (Lp=6)")
PyPlot.xlabel("time")
PyPlot.ylabel("frequency")
PyPlot.legend(["Tracking A","Tracking B"])
PyPlot.ylim(0,120)


    

    













    
Out[7]:





(0, 120)

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