Hi Whats the difference between these 2? I'm new to Gnuradio & python to be honest; I'm writing my own ap25 listener for the funcube... So far, I've got my software tuning, FM decoding, and then sending data into the FSK4 decoder; I can see it fine tuning.. but I don't get anything out of the decoder_bf function. Is there any easy way, to debug what its doing?? Digging around in code there doesn't seem to be much debugging. I did create some network sinks, and forward the output of the FM demod to a a scope inside gnuradio companion.. the signal looks like FSK4 with the funky phase changes. Sean
Hi, I've just got a funcube myself and just this morning support for it made it into the GNURadio trunk. That should make using them lots easier. I am looking forward to seeing the DVB-T support get done because that will make using SDR *much* cheaper (23USD delivered!). The question you ask concerns the interface to the decoder... the _ff version has float inputs and outputs and the other takes bytes (actually two-bit symbols) inputs and float outputs. The latter needs a slicer before it but that is conceptually the right thing to do and so the _ff version is deprecated. Hope that helps. Stevie On 23 March 2012 07:48, bdapriv01 <bdapriv01@gmail.com> wrote:
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Hi
Whats the difference between these 2?
I'm new to Gnuradio & python to be honest; I'm writing my own ap25 listener for the funcube...
So far, I've got my software tuning, FM decoding, and then sending data into the FSK4 decoder; I can see it fine tuning.. but I don't get anything out of the decoder_bf function.
Is there any easy way, to debug what its doing??
Digging around in code there doesn't seem to be much debugging.
I did create some network sinks, and forward the output of the FM demod to a a scope inside gnuradio companion.. the signal looks like FSK4 with the funky phase changes.
Sean
DVD-T? Really? What kind of receiver just a usb ATSC tuner etc? Scary to what to think I could do with DVB-S2 and Gnuradio lol Ok great Back to the decoder ff that fills in some blanks. I put a slicer ahead of the decoder - now I get segv inside the decoder - inside the general_work method: (running python under gdb...) [New Thread 0x7fffdc1bd700 (LWP 9511)] Program received signal SIGSEGV, Segmentation fault. [Switching to Thread 0x7fffdc9be700 (LWP 9510)] op25_decoder_bf::general_work (this=0x27666b0, nof_output_items=46,nof_input_items=..., input_items=<value optimized out>, output_items=...) at op25_decoder_bf.cc:92 92 float *out = reinterpret_cast<float*>(output_items[0]); (gdb) bt #0 op25_decoder_bf::general_work (this=0x27666b0, nof_output_items=46, nof_input_items=..., input_items=<value optimized out>, output_items=...) at op25_decoder_bf.cc:92 #1 0x00007ffff5f01a3e in gr_block_executor::run_one_iteration() () from /usr/local/lib/libgnuradio-core-3.5.3git.so.0.0.0 #2 0x00007ffff5f232cf in gr_tpb_thread_body::gr_tpb_thread_body(boost::shared_ptr<gr_block>, int) () from /usr/local/lib/libgnuradio-core-3.5.3git.so.0.0.0 #3 0x00007ffff5f1c71f in boost::detail::function::void_function_obj_invoker0<gruel::thread_body_wrapp er<tpb_container>, void>::invoke(boost::detail::function::function_buffer&) () from /usr/local/lib/libgnuradio-core-3.5.3git.so.0.0.0 #4 0x00007ffff5c4d015 in boost::detail::thread_data<boost::function0<void>
::run() () from /usr/local/lib/libgruel-3.5.3git.so.0.0.0 #5 0x00007ffff5193b70 in thread_proxy () from /usr/lib/libboost_thread.so.1.40.0 #6 0x00007ffff7bc69ca in start_thread () from /lib/libpthread.so.0 #7 0x00007ffff6aa0cdd in clone () from /lib/libc.so.6 #8 0x0000000000000000 in ?? () (gdb)
The code in question looks like: int op25_decoder_bf::general_work(int nof_output_items, gr_vector_int& nof_input_ite ms, gr_vector_const_void_star& input_items, gr_vector_void_star& output_items) { ... float *out = reinterpret_cast<float*>(output_items[0]); I'm not totally familiar with blocks in GNURadio - seems like output_items isn't initialized... Sean From: op25-dev@yahoogroups.com [mailto:op25-dev@yahoogroups.com] On Behalf Of Steve Glass Sent: Thursday, March 22, 2012 6:49 PM To: op25-dev@yahoogroups.com Subject: Re: [op25-dev] difference between op25.decoder_bf and op25.decoder_ff Hi, I've just got a funcube myself and just this morning support for it made it into the GNURadio trunk. That should make using them lots easier. I am looking forward to seeing the DVB-T support get done because that will make using SDR much cheaper (23USD delivered!). The question you ask concerns the interface to the decoder... the _ff version has float inputs and outputs and the other takes bytes (actually two-bit symbols) inputs and float outputs. The latter needs a slicer before it but that is conceptually the right thing to do and so the _ff version is deprecated. Hope that helps. Stevie On 23 March 2012 07:48, bdapriv01 <bdapriv01@gmail.com> wrote: Hi Whats the difference between these 2? I'm new to Gnuradio & python to be honest; I'm writing my own ap25 listener for the funcube... So far, I've got my software tuning, FM decoding, and then sending data into the FSK4 decoder; I can see it fine tuning.. but I don't get anything out of the decoder_bf function. Is there any easy way, to debug what its doing?? Digging around in code there doesn't seem to be much debugging. I did create some network sinks, and forward the output of the FM demod to a a scope inside gnuradio companion.. the signal looks like FSK4 with the funky phase changes. Sean
You can find out more about the DVB-T receiver here: http://sdr.osmocom.org/trac/blog/rtl-sdr-introduction Not sure what's wrong with your program but the output_items should be set by the caller and provides a bugger into which the float outputs are written. No need to re-invent the wheel here though - just cut&paste from one of the other receivers.
participants (3)
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bdapriv01 -
Sean Watkins -
Steve Glass