[Discuss-gnuradio] Bug in freq_xlating_fir_filter_XXX

[Achilleas Anastasopoulos]

I was playing around with

fir_filter_XXX

and

freq_xlating_fir_filter_XXX

and noticed that the two do not give the same output

for the same input (and center_freq=0 in the xlating filter).

Looking at the implementation of the latter

it is obvious why: the taps are reversed in the line:

std::reverse(ctaps.begin(), ctaps.end());

For consistency the taps should not be reversed (as in all other filters)

We also need to set

float fwT0 = 2 * M_PI * d_center_freq / d_sampling_freq;

(instead of the minus sign in the code).

unless there is an objection, I will go ahead and push a correction,
Achilleas