Re: [Discuss-gnuradio] Processing multiple signals off single source block

[Vanush Vaswani]

Mike, does this work with the Funcube Dongle Pro+?

On Thu, Aug 22, 2013 at 4:39 AM, Mike Jameson <address@hidden> wrote:

Hi Luke,

I've found using the FFT blocks are the most cpu efficient way to extract a channel from the whole 20MHz of the HackRF.  Have a look at my latest Scanoo release built in GRC which uses the 'Keep X in N' block to select the channel required.  There's also a spectrum sense mode which locks on to the strongest signal within the 20MHz bandwidth if it is not in the blocked frequency list:

https://github.com/m0mik/scanoo

Cheers,

Mike

--
Mike Jameson M0MIK BSc MIET
Email: address@hidden
Web: http://scanoo.com

On Wed, Aug 21, 2013 at 7:15 PM, Luke B <address@hidden> wrote:

I am working on a processing multiple signals using a single source block. The background is below, but I had a couple of high level questions:

 

 - What is the best approach performance wise for selecting multiple ~15khz channels from a 2mhz+ source block? Is it using a Xlating FIR Filter with a low-pass? Is it more efficient to use a SIN Sig source & Multiply Block with a low-pass FIR Filter? Is there a better way to extract a filter?

 

 - What is the best way to have different bunch of blocks processing each signal run independently and not block each other? I want to do this as a GR C++ program is there any way to run the signal source and chanelizers as one thread and then have the different processing chains run as separate threads? Is there a way to put a queue or buffer inbetween blocks that would allow for a chain of blocks to be separated between threads?

 

Or am I better off doing the basic signal/channel processing for everything in a single process and then writing the results to a file and then having a process which goes through the files and does the more intensive vocoder work in non-real time? 

 

Any pointers or examples of how to do threading with GR C++ code would be really helpful. I am not sure of the best architectual approach.

 

 

Background:

I have taken the gr-smartnet code and done a skeleton implementation in C++. I want to process the digital trunking channel and then decode and record the digital audio from all of the different talk groups. Since it is trunked, channels will be randomly be turning on and off and talk groups will be switching from channels. It would be good to have a separate thread for the trunk decoding and the separate digital audio recorders. Ideally, I would like to be able to do this over 8 or 10Mhz using my HackRF.

 

My code, which is working enough to decode the trunking channel, is here: https://github.com/robotastic/sdr

 

Thanks!

 

 - Luke

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