I am having difficulty using gr::filter::firdes in my OOT cpp block.
(Trying to use code block in notorious webmail editor for gmail, sorry if
this gets a little garbled)
I am calling my setter function as follows...
```cpp
set_filter( 31.25f, 50.0f, 96.0f );
```
And this is the setter function at the moment while I am troubleshooting...
```cpp
void
my_sink_c_impl::set_filter( float passband, float stopband, float
attenuation ) {
std::printf( "set_filter samp_rate %f passband %f stopband %f
attenuation %f\n", d_samp_rate, passband, stopband, attenuation );
delete d_in_decim_lpf;
std::printf( "set_filter 1\n" );
gr_vector_float taps = gr::filter::firdes::low_pass_2( 1, 1, 0.2,
0.1, 60 );
/*
gr_vector_float taps = gr::filter::firdes::low_pass_2(
1,
d_samp_rate,
( stopband - passband ) / 2, // 'cutoff' (center of transition
band) or just passband (beginning of transition band)?
stopband - passband,
attenuation,
gr::filter::firdes::WIN_BLACKMAN_hARRIS
);
*/
std::printf( "set_filter 2\n" );
//d_in_decim_lpf = new gr::filter::kernel::fft_filter_ccf(
d_samp_per_sym, taps, 1 );
std::printf( "set_filter 3\n" );
//d_in_filt_samp_per_step = d_in_decim_lpf->set_taps( taps );
std::printf( "set_filter 4\n" );
}
```
Note that my block does not do anything with d_in_decim_lpf (or
d_in_filt_samp_per_step
for that matter) yet except try to set it up by calling this from the
constructor.
When I make clean / make / sudo make install / sudo ldconfig, then reload
blocks in grc and try to run my flowgraph...
It prints the first printf (with the params) and then stops with a return
value of -11 (segfault?)
My guess is that the second printf ('1') works but is interrupted before
executing by an error in the next line
It does this regardless of whether I uncomment/comment the firdes call the
way I want it (the multline version) or use the firdes call I copied from
Tom Rondeau's (albeit pythonic - maybe I am goofing my translation to cpp)
ageless example shown.
I tried leaving off the window type (using the default Hamming) but that
was not it.
Since the values might be a little extreme for my 2k sample rate I am using
(64 x cutoff freq) I also tried it with Tom's old example.
If I comment out both versions of trying to call firdes to generate taps,
then it prints all the goodies and the flowgraph runs fine.
I must be doing something wrong at a basic level here. Any ideas?
Thanks.
John
