[Discuss-gnuradio] Increase sine frequency every N samples

[Carlos Aviles]

Hi,

I want to generate a sine wave that increases in some kHz its
frequency every N samples it produces.

I know I can change the frequency of the sine using the available
setter method on the gr_sig_source block. My problem is how to perform
that change exactly after N samples have been produced by the
gr_sig_source block. I've come up with some ideas:

- Make the top_block aware of the number of samples that the
gr_sig_source has produced. When N samples are produced, the top_block
could call Lock(), change the parameter, and then Unlock(). My problem
here is how to make the top_block aware of that count. I could use a
"listener block" just after the gr_sig_source and let it count the
samples that pass through it. After N samples, it could trigger some
signal to the top block. I don't like this approach because it seems
too complex.

- Extend the functionality of gr_sig_source to increase the frequency
by itself. By directly extending the class that won't work because
there is no public constructor for gr_sig_source. Is there any other
way of doing that?

- Save N samples of different sine waves into files and then generate
a single one by concatenation. I could use then a file_source block to
incorporate these sine waves into any flow graph. The problem is the
size of the resulting file.

I would appreciate very much any help on that.

I'm using gnuradio-3.2.2 and I want to generate a 100% C++ application.

Thanks,
Carlos.

PS: I haven't posted any code because I don't have any yet :)