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Re: [Discuss-gnuradio] Hello GNURadio from the Amateur Radio World
From: |
Marcus D. Leech |
Subject: |
Re: [Discuss-gnuradio] Hello GNURadio from the Amateur Radio World |
Date: |
Sat, 26 May 2018 22:10:15 -0400 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 |
On 05/26/2018 09:44 PM, Dan CaJacob wrote:
Will,
I think you will find a wide variety of real-world applications
GNURadio has been used for. For myself, that includes ground to space
and space to ground communications systems, encompassing both common
desktop machines as well as embedded processors and FPGAs. Certainly
it is easier to write a modem for a desktop CPU, but a good C++
developer (I am not one, but I work with them) can take advantage of
pipelined operations in both embedded and desktop CPUs to make
distinction between the platforms less crippling. The Volk project
even makes this win more or less free (no need to write your own
instrinsics) if you profile it for your specific embedded device.
That said, I notice a lot of people new to GR wanting to jump right
into doing something hard on a Raspberry Pi or similar SBC. I think
you'll find that's generally a mistake. I'd suggest getting
comfortable with GR and SDR on the desktop before moving on to
embedded systems, because there's a lot to learn in both and it's
going to be worse if you have to learn them both at the same time.
- Dan
Another thing I find is that there's a big gap in comprehension about
how much 'stuff' happens to each and every sample for even relatively simple
(from a 10kft view) DSP flows.
"My CPU runs at 2.5GHz, and I'm only bringing in a measly 10MHz, why is
this not working for me?"
"Why can't I make a precipitously-steep filter--this is software, after
all. It's all kinda virtual, right?"
Folks who are coming at this from the "apps" world may never have
considered or experienced or pondered exactly what happens inside
the "sausage factory" we call a modern operating system.
"Sample-arrives---->[MAGIC]----->it's in my app---->[MORE
MAGIC]---->cool stuff happens".
If you're coming from a world where real-world "events" happen at the
rate of user-clicks, thinking about being responsive to "events" that may be
happening millions of times per second may be a bit of a cognitive
shock...
Just random thoughts from years and years watching this ballet play out....