Re: [Discuss-gnuradio] forum to learn more about signal-processing and SDR ?

[Kristoff]

Hi Quasin, Neel, Ali, Albin,


(I'll reply in everybody in one mail, this list is busy enough as it is 
:-) )


Ali, Neel,

Thanks for the link.

Also I agree that basic-information is important to get started, in this 
case, I was looking for a forum/list. Sometimes, one needs to have a 
place to just as a question on a particular issue or how it is 
implemented in a specific project.

In this case, my question was related to a APT decoder found here 
(http://oz9aec.net/radios/gnu-radio/simple-apt-decoder-prototype), and  
more specific how the AM demodulation is done. It uses a trick to shift 
the spectrum of a IQ signal down by 1/4 the sampling-rate, but I did not 
understand why he does one single conversion from 2 floats to a complex 
(s1, s2 -> [s1,s2]). and not two (s1,s2,s3,s4 -> [s1,s2],[-s3,-s4])
In the mean time, I found it out myself: as the next block is a 
complex-to-amplitude, the sign of the complex number is removed anyway.


I don(t know if this the same for other people new to signal-processing, 
GNU Radio is very interesting as it allows me to look at how other 
people do it and learn from that. Hence, having a forum to ask questions 
is a real forum.


Albin, Quasim,

Thanks for the link.
The "dsprelated" forum seams quite interesting.


The problem with stack-exchange (I have noticed) is that you really must 
have a very specific answer with a very specific answer. They do not 
like "generic" questions. (I once had a question on amateur-radio 
refused by them as it was "not precise enough").


Thanks!


Kristoff



On 18/03/19 00:55, Qasim Chaudhari wrote:
> Hi Kristoff,
>
>    Since you've asked about a forum, I think DSPrelated is a treasure 
> trove of DSP knowledge. Hope you find it useful.
>
> https://www.dsprelated.com/forums
>
> Cheers,
> Qasim