Re: [Discuss-gnuradio] Help understanding the role of IF_freq in this snipper of code

[Eric Blossom]

On Thu, Aug 06, 2009 at 05:47:22PM -0400, Jonathan Coveney wrote:
> http://www.linuxjournal.com/article/7505
> This article is a useful one I've studied to understand FM demodulation
> 
> In the block of code that implements (albeit I haven't tried to run it
> because it's not made to run with a USRP, it's more pedagogical), to
> demodulate two frequencies, it averages them and then centers them around an
> IF_freq.
> 
> My guess is that this is the frequency that serves as a "0" post
> demodulation. Ie by reading frequency 5.75e6, you are reading the 0
> frequency. But I'm not sure.
>
> If this is the case, if I wanted to implement something similar using the
> USRP and TVRX, is there a similar "center" that I need to use? Is it 5.75e6?
> or is it simply 0hz?

0 Hz.

Please take a look at usrp_wfm_rcv2_nogui.py

Eric