Help understanding the role of IF_freq in this snipper of code

GNU Radio
1

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?

I’ve attached the code.

Thanks

2

On Thu, Aug 06, 2009 at 05:47:22PM -0400, Jonathan C. wrote:

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