Re: [Discuss-gnuradio] Strange problem when reading from gr.GR_SIN_WAVE.....

[Eric Blossom]

On Thu, Nov 29, 2007 at 05:59:44PM -0500, Kshitij Singh wrote:
> Hi all,
> 
>     I am a newbie to GNU Radio. I just started off with my first program and
> decided to read some floating point samples from the gr.GR_SIN_WAVE into a
> file. My problem is that every time I run the program, I get a different
> file size. I even tried to change the file name after the first run, but
> again ended up with the same problem. Here's the script:
> ------------------------------------------------------------
> 
> from gnuradio import gr
> import time
> 
> def my_graph():
>         sampling_frequency = 10000
>         amplitude =0.1
>         graph1 = gr.flow_graph()
>         source = gr.sig_source_f(sampling_frequency,gr.GR_SIN_WAVE
> ,100,amplitude)
>         destination = gr.file_sink(gr.sizeof_float,
> '/home/anshul/Desktop/samples1.dat')
>         graph1.connect(source,destination)
>         return graph1
> 
> if __name__ == '__main__':
>         graph1 = my_graph()
>         graph1.start()
>         time.sleep(2e-6)
>         graph1.stop()
> ------------------------------------------------------------------
> 
> kindly help out with this. Thanks in advance.

Insert a 

  head = gr.head(gr.sizeof_float, N)

between your source destination, where N is the number of samples you
want to collect.

Eric