Hello,

I’m trying to make an FFT block in my hierarchical block, but I cannot

seem to find the correct syntax.

I’m trying to make it with a BLACKMAN_HARRIS windowing function, and

it’s easy in a python program:

```
fft_forward = fft.fft_vfc(window_size, True,
```

(fft.blackmanharris(window_size)), 1)

fft_backward = fft.fft_vcc(window_size, False,

(fft.blackmanharris(window_size)), False, 1)

But in a c++ program it gets hairy. Does anyone have any experience with

this?

```
gr::fft::fft_vfc::sptr fft_forward = gr::fft::fft_vfc::make(SIZE,
```

true, gr::filter::firdes::WIN_BLACKMAN_HARRIS, num_threads);

gr::fft::fft:vcc::sptr fft_reverse = gr::fft::fft_vcc::make(SIZE,

false, gr::filter::firdes::WIN_BLACKMAN_HARRIS, false, num_threads);

I believe what I have wrong is the Windowing, which is of the form:

```
const std::vector< float > & window
```

Sincerely,

Tommy James Tracy II

Ph.D Student

High Performance Low Power Lab

University of Virginia

Phone: 913-775-2241