RE: [Discuss-gnuradio] Demo Audio Code

[Ettus, Matt]

> 
> Thanks for the code tip. I will look into it but not for 
> WWVB. There is not phase/frequency modulation on WWVB only 
> the two-level ASK. (So admittedly there would be two dots.) 

That's exactly why it is perfect for WWVB.  A PLL is the best way to
demodulate AM.  The FPLL tracks the frequency, and generates a phase-locked
carrier reference.  This is especially useful for WWVB, where you do care
about the exact carrier frequency.  Then you mix that reference with the
transmitted signal to get the amplitude variation out of it.

> The timing of the levels carries a binary time code. The 
> carrier frequency can also be used as a potentially very 
> accurate phase/frequency reference with the customary 
> limitations on atmospheric propagation. For my location (only 
> a few miles from the transmitter) it is very good.

Matt