what is 'parm' means when you set the name of wavelet function in cwtft
or icwtft
. wave = {wname,[7.6]}
. also can I change Fb and Fc when I use 'morl'
function in cwtft
or icwtft
transform? and If not, then how can I reconstruct my signal with cwt transform? cause cwt let me to select optional value for fb and fc (cmorfb-fc
). Matlab doesn't have direct function for inverse wavelet transform.
N = 1024;
t = linspace(0,1,N);
y = sin(2*pi*8*t).*(t<=0.5)+sin(2*pi*16*t).*(t>0.5);
dt = 0.05;s0 = 2*dt;ds = 0.4875;NbSc = 20;
wname = 'morl';sig = {y,dt};sca = {s0,ds,NbSc};
wave = {wname,[7.6]};
cwtsig = cwtft(sig,'scales',sca,'wavelet',wave);
sigrec = icwtft(cwtsig,'signal',sig,'plot');
thought someone need the answer.
cwtft
andicwtft
use Fourier transform of wavelet function to reconstruct the signal. The ‘morl
’ in wname is analytic morlet function. So it’s exactly complex morlet and will give you phase and magnitude information about signal. The ‘parm’ inwave={‘morl’,[parm]}
is wo or2*pi*fc
. So it’s corresponded to center frequency. Default value of ‘parm’ is 6 sofc=6/2*pi
.molet wavelet function ispsi(t,fc)=exp(j*2*pi*fc*t)*exp(-t^2/2
) and its Fourier transform ispsi^(k)=sqrt(2*pi)exp(-0.5(2*pi*k-ko)^2)
.ko= parm = 2*pi*fc.
so you can config fc of morlet wavelet with changing parm. dunno how to make formulation nice. someone edit it plz.