Open kylmcgr opened 10 months ago
Hi Kyle. First of all, my apologies for taking so long to get to this.
I apologize for the confusion in the code. In fact, final_filt_result
(the output of filter(), reversing, filter() again, then reversing again) is the same as the output of filtfilt()
. If you have the signal processing toolbox, you can just use filtfilt()
; if you don't have the signal processing toolbox, you'd use filter() twice to get the variable final_filt_result
. I put it in the code for people to see how to apply a zero-phase-shift filter without the signal processing toolbox.
No worries, and that makes sense! Correct me if I'm wrong, but it looks like reverse_filt
is just filter(), reversing, and filter() without the second reversal. Super minor and doesn't really effect the plot, but it seems like it did mean to be final_filt_result
plotted instead in Figure 14.9? I put the relevant code snippet below.
forward_filt = filter(filterweights,1,wavelet);
reverse_filt = filter(filterweights,1,forward_filt(end:-1:1));
final_filt_result = reverse_filt(end:-1:1); % must reverse time again!
figure
plot(wavelet)
hold on
plot(forward_filt,'r')
plot(reverse_filt,'m')
The variable
final_filt_result
gets defined but is never used in chapter 14. I assume that it is supposed to be plotted after it is calculated in Figure 14.9 instead ofreverse_filt
. It looks likereverse_filt
is close enough to symmetrical that there isn't a visible effect on the plot itself, but thought I would still mention it anyways. Thanks!