Philip Balister | 2 Jul 19:35 2015

Re: Writing RSSI Values to a File Twice/Sec

On 07/02/2015 11:25 AM, Varun Nambiar wrote:
> Hi Philip,
> 
> At the moment of execution a file size of 32KB with just 0s is written to my file and then it doesn't add
anymore values after that. I am on release-2 and I've attached my GRC file.

I dropped the throttle block and saw the output file get larger. Resend
the flowgraph to the list and maybe someone else has some ideas how to
make it better.

Philip

> 
> Thank you,
> Varun
> 
> ________________________________________
> From: Philip Balister <philip <at> balister.org>
> Sent: Thursday, July 2, 2015 11:18 AM
> To: Varun Nambiar; discuss-gnuradio <at> gnu.org
> Subject: Re: [Discuss-gnuradio] Writing RSSI Values to a File Twice/Sec
> 
> On 07/02/2015 11:07 AM, Varun Nambiar wrote:
>> Hi all,
>>
>>
>> I'm new to GNURadio and I'm trying to use a USRP E310 to capture GSM signals from a cellphone and store the
RSSI values in a text file. If you take a look at my flow graph I've managed to capture the average strength
across the 200kHz GSM band and I'm trying to filter out the unwanted signals using the Probe Avg Mag^2 block.
>>
(Continue reading)

Varun Nambiar | 2 Jul 17:07 2015

Writing RSSI Values to a File Twice/Sec

Hi all,


I'm new to GNURadio and I'm trying to use a USRP E310 to capture GSM signals from a cellphone and store the RSSI values in a text file. If you take a look at my flow graph I've managed to capture the average strength across the 200kHz GSM band and I'm trying to filter out the unwanted signals using the Probe Avg Mag^2 block.


I'm having trouble writing to the file sink at a constant 2 samp/sec. Could you please give me advice on how I should fix my flow graph?


Thank you,

Varun

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Jeon | 2 Jul 17:03 2015
Picon

Is a unipolar signal bad as an input for a USRP receiver?

I am using LFTX and LFRX to transmit and receive data between two nodes.

I am modulating a bit stream with on-off keying (OOK) in which bit 1 is modulated into HIGH voltage and bit 0 is modulated into LOW voltage close to zero.

What I concern is, USRP can process bipolar signal, has a low noise amplifier (LNA) and an ADC at the receiving end. I've heard that LNA and ADC take a heavy stress if they process a unipolar, a DC biased signal.I want the statement to be clear. I have a particular condition that I can't make a transmitted signal a bipolar NRZ signal instead of OOK...

PS. I make a thread in discuss-gnuradio since I've got no reply on USRP-users several days or weeks ago (I don't remember exactly...).

Regards,
Jeon.
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Salija P | 2 Jul 08:23 2015
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PCCC Decoder Combo- OFDM

Hello,
 I am usin OFDM Modulation and demodulation along with PCCC  encoder and PCCC decoder..  I am using QPSK modulation in OFDM. But Pccc decoder combo also using Demodulation parameter Constellation and Dimension. is it mean that demodulating twice?  how can I use OFDM Block with PCCC decoder?
Can anybody help me? I am new to this.

Thanks in Advance.











With Regards,
Salija.P
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Salija P | 2 Jul 07:30 2015
Picon

PCCC Decoder Combo- Ofdm


Hello,
 I am usin OFDM Modulation and demodulation along with PCCC  encoder and PCCC decoder..  I am using QPSK modulation in OFDM. But Pccc decoder combo also using Demodulation parameter Constellation and Dimension. is it mean that demodulating twice?  how can I use OFDM Block with PCCC decoder?
Can anybody help me? I am new to this.

Thanks in Advance.







With Regards,
Salija.P
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Salija P | 2 Jul 07:23 2015
Picon

Pccc Decoder with OFDM


Hello,
 I am usin OFDM Modulation and demodulation along with PCCC  encoder and PCCC decoder..  I am using QPSK modulation in OFDM. But Pccc decoder combo also using Demodulation parameter Constellation and Dimension. is it mean that demodulating twice?  how can I use OFDM Block with PCCC decoder?
Can anybody help me? I am new to this.

Thanks in Advance.








With Regards,
Salija.Pg
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Jared Dulmage | 2 Jul 05:11 2015

block::system_handler done message format

As I was investigating the message passing subsystem I noticed that my own blocks had a "system" port that I
did not manually register.  Looking through the code I found in block.cc the special message to put the
block in a finished state:

void
  block::system_handler(pmt::pmt_t msg)
  {
    //std::cout << "system_handler " << msg << "\n";
    pmt::pmt_t op = pmt::car(msg);
    if(pmt::eqv(op, pmt::mp("done"))){
        d_finished = pmt::to_long(pmt::cdr(msg));
        global_block_registry.notify_blk(alias());
    } else {
        std::cout << "WARNING: bad message op on system port!\n";
        pmt::print(msg);
    }
  }

Maybe I don't understand the reason for this, but it appears that this code requires pmt::cdr(msg) to
return a long int and then implicitly casts to a bool.  Wouldn't it be better for this to be a bool already such
that a message could be constructed like

pmt::cons(pmt::mp("done"), pmt::get_PMT_T())

or Python

pmt.cons(pmt.to_pmt("done"), pmt.PMT_T)  ?

Perhaps it really doesn't matter.  It just seems more natural, particularly if one were to put a logical
statement as the argument to pmt::cons.

Jared.
------------------------------------------------------
Jared Dulmage
Engineering Specialist
Digital Comm. and Implementation Dept.
Aerospace Corporation
310-336-3140
Jared Dulmage | 2 Jul 04:55 2015

message passing: strobe or _post?

I am testing the capability of posting messages to Python blocks via Python.  I have included below a simple
example in which the Python block just prints out the message received.  In one case, I send messages to this
block via the builtin gnuradio.blocks.message_strobe block.  In the other case I try to call _post on the
block directly from Python.  The former case works, but not the latter.  I've tried to delve into the code,
but so far have not found an answer.  Any advice would be appreciated.

Jared.

Ubuntu 14.04
Python 2.7.6
GR 3.7.8

#!/usr/bin/env python
##################################################
# Message passing example
# Jared Dulmage
#
##################################################

from gnuradio import gr, blocks
import pmt
import json
import time

class message_print(gr.sync_block):
    def __init__(self):
        gr.sync_block.__init__(self, "message_print", None, None)

        self.msg_port = mport = "in_port"
        self.message_port_register_in(pmt.intern(mport))
        self.set_msg_handler(pmt.intern(mport), self.print_msg)

    def print_msg(self, msg):
        print "RECEIVED: ",
        print json.dumps(pmt.to_python(msg))

def main(*args):
    if "strobe" in args:
      main_strobe()
    else:
      main_no_strobe()

def main_no_strobe():
      tb = gr.top_block()
      msg_printer = message_print()
      tb.connect(msg_printer)
      tb.start()
      for n in range(10):
        time.sleep(0.1)
        msg_printer.to_basic_block()._post(pmt.intern(msg_printer.msg_port),
                                           pmt.to_pmt({'NUM': n}))
      tb.stop()
      tb.wait()

def main_strobe():
      tb = gr.top_block()
      msg_printer = message_print()
      msg_strobe = blocks.message_strobe(pmt.to_pmt({'NUM': -1}), 100)
      tb.msg_connect(msg_strobe, "strobe", msg_printer, msg_printer.msg_port)
      tb.start()
      time.sleep(1)
      tb.stop()
      tb.wait()

if __name__ == '__main__':
    import sys
    sys.exit(main(*sys.argv[1:]))

------------------------------------------------------
Jared Dulmage
Engineering Specialist
Digital Comm. and Implementation Dept.
Aerospace Corporation
310-336-3140
Anderson, Douglas J. | 1 Jul 23:16 2015

gr-lte chanel estimation

Hi all,

I'm working at putting together a flowgraph based on gr-lte.

For the channel estimator hier block [1], it looks like there are two RS map generators, one for each of 2 "antenna ports".

I only have one antenna connected to my USRP N210. Is this a problem? Do I still use 2 RS map generators with antenna port 0 and 1?

-Doug

[1] https://raw.githubusercontent.com/kit-cel/gr-lte/master/docs/lte_estimator_hier.grc.png

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marco Ribero | 1 Jul 22:23 2015
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Install UHD after GNURadio installation

Hi,
now I need to install also the UHD module of gnuradio(before I've used only RTL). Is possible to install this module without reinstall the entire gnuradio?
I've tried the easiest apprach, mkdir/cmake/make.. in gnuradio/gr-uhd, but it doesn't work.

Thanks,
marco
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Nguyễn Văn Lý | 1 Jul 12:14 2015
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Loading FPGA file to 4 bladeRF devices on a single laptop

Hi all,

I want to use 4 bladeRF devices on a single laptop. This means I have to load the FPGA file to all of 4 bladeRF devices. 
However, currently I can only load the PFGA file to 2 devices.
I am using the command: 

bladeRF-cli -l <path/to/FPGA/file>

Does anyone know how to load the FPGA file to 4 bladeRF devices on a single laptop? Please help me with this!
Thank you in advance.

Best Regards,
Van-Ly

Van-Ly Nguyen,
Research Assistant, 
Signals and Systems Laboratory - SSL  
Faculty of Electronics and Telecommunications - FET         
University of Engineering and Technology - UET      
Vietnam National University, Hanoi - VNU  

Phone: (+84) 97 881 9406

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