Re: [Discuss-gnuradio] Creating a signal source block using Python

[Anisha Gorur]

It works now, thanks! It was a combination of a couple dumb errors on my part. One last thing, I was wondering if there was a way to change the length of output_items[0]? It is 4096 by default I believe.

Thanks,

Anisha

On Thu, Jul 19, 2012 at 2:13 PM, Josh Blum <address@hidden> wrote:

On 07/18/2012 11:32 AM, Anisha Gorur wrote:
> Hello All,
>
> I've been attempting to create my own source block in Python. I have been
> reading the blocks coding guide here:
> https://github.com/guruofquality/grextras/wiki/Blocks-Coding-Guide#wiki-work-operation-modes,
> but so far my source only outputs zeros.
> An outline of my code is as follows:
>
> class constSource(gr.block):
> def __init__(self):
>                  gr.block.__init__(self, name = "signal source", in_sig =
> None,out_sig = [numpy.complex64])
>
> def work(self, input_items, output_items):
>                num_output_items = len(output_items[0])
>
>          #I put the code to create what I want to stream here, the code
> creates a numpy.complex64 array with a length of 32. I then return
> num_output_items

You didnt include the code, but I am guessing that you are not assigning
anything to the output vector?

numpy array assignment look like this
output_items[0][some kind of index selection] = data

Look closely at how the examples do this

-josh

>           return num_output_items
>
> I then write my constSource block to a file and I try to see the output of
> the file using a scope sink, but it is just a constant stream of zeros. Am

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--
Anisha Gorur
Class of 2012
Electrical Engineering