|Subject:||Re: [Discuss-gnuradio] FSK performance as a function of Fd?|
|Date:||Sun, 16 Dec 2012 23:36:56 -0500|
On Sun, Dec 16, 2012 at 11:27:47PM +0100, Joanna Rutkowska wrote:I believe you are correct that sensitivity vs. deviation is strongly
> Thanks for the detailed answer! I did some more study and my
> understating is that what you wrote above applies to (theoretical)
> coherent demodulation. AFAIU nearly all practical receivers use
> non-coherent demodulation (because it's cheaper, and apparently, has
> about 1dB penalty only on sensitivity?). This non-coherent detection
> is apparently realized using two bandpass filters centered around the
> two frequencies.
dependent on the receiver implementation. You may not be correct
assuming anything about the particular receiver implementation in the
Making a guess about the receiver implementation, I'd say you correctly
> So, my understanding goes, in any practical realization, it should be
> better (not worse at least) to use as large Fd as one can, because it
> makes the job of the two filters easier...
> But, it's apparently not like this. Here's the link to the Atmel paper
> I mentioned before (again, please take a look at Figure 9-2):
describe why the sensitivity improves as Fd increases toward 50 kHz.
I'd further guess that the reason sensitivity gets worse above 50 kHz
deviation is that the bandwidth of the signal exceeds the fixed IF
filter in the receiver.
|[Prev in Thread]||Current Thread||[Next in Thread]|