Re: [Discuss-gnuradio] control time or number of points acquired

[ematlis]

Thanks Eric, Juha, and Michael-

to get 3 helpful responses within an hour of sending a post is truly 
amazing, particularly considering the time of the year.

I should have elaborated in my post.  I tried the gr.head approach, but 
I'm not sure it works in my application- I'm using the approach of the 
astronomy guys, with a control button that turns on and off from /dev/null 
to a file descriptor.  So if I use gr.head, correct me if I'm wrong, but I 
believe it immediately sends the number of samples specified to /dev/null. 
I don't think that way is compatible with the approach I'm using, which I 
ripped off from usrp_psr_receiver.py.

So you know what I'm doing, I'm using the USRP as a pseudo digital 
oscilloscope with a capture to file option.  When I see something I like 
in the scope, I hit the "capture to file" button.  It works great, but 
currently I have to look at my watch to capture comparably sized samples.

Perhaps there's a way of incorporating a timed capture (or fixed number of 
samples to this model?

thanks again so much.

eric

************************************
Eric H. Matlis, Ph.D.
Aerospace & Mechanical Engineering Dept.
120 Hessert Center for Aerospace Research
University of Notre Dame
Notre Dame, IN 46556-5684
Phone: (574) 631-6054
Fax:   (574) 631-8355

On Sat, 22 Dec 2007, Eric Blossom wrote:

> On Sat, Dec 22, 2007 at 06:04:50PM -0500, address@hidden wrote:
> > Hi all-
> >
> > has anybody implemented a control whereby the user can limit how long or
> > how many points gets acquired by a gnuradio application?  If so I'd
> > appreciate any pointers!  I've got an app where I'm storing samples to file
> > and I'd like to control how many points go into each data file.
> >
> > thanks,
> > eric
>
> Hi Eric,
>
> We generally use gr.head for this.
> See gr-utils/src/python/usrp_rx_cfile.py
>
> Eric