QAM Mod and QAM Demod block in GRC

GNU Radio
1

Hi all,

I’m working on an experiment which needs to modify qam modulation block
in
gnuradio. But I cannot find the source C++ file the qam blocks use.
e.g.,
OFDM demod block uses digital_ofdm_frame_sink in
gnuradiobuild/gnuradio/gr-digital/lib. What about qam blocks?

Thank you for your help!

Best,

jia

2

I am using USRP2 device my device works fine with GNU radio.
O.S=Ubuntu 10.04
Ip settings 192.168.10.1 netmask 255.255.255.0

I tested the firewall is disabled by using
umer@umer:~/Downloads$ sudo ufw status
Status: inactive

I want to ping the ip address 192.168.10.2 but the response is
unreachable.

I have tried changing the ip address by using

umer@umer:~/Downloads$ sudo ./usrp2_recovery.py --ifc=eth0
–new-ip=192.168.10.2(‘Opening raw socket on interface:’, ‘eth0’)
(‘Loading packet with ip address:’, ‘192.168.10.2’)
Sending packet (22 bytes)
Done

Umer

3

On Thu, May 31, 2012 at 05:01:56PM +0100, [email protected] wrote:

I am using USRP2 device my device works fine with GNU radio.

Hm, so what exactly is your problem?

O.S=Ubuntu 10.04
Ip settings 192.168.10.1 netmask 255.255.255.0

I tested the firewall is disabled by using
umer@umer:~/Downloads$ sudo ufw status
Status: inactive

I want to ping the ip address 192.168.10.2 but the response is unreachable.

I don’t think you can ping USRP2s.

MB

–
Karlsruhe Institute of Technology (KIT)
Communications Engineering Lab (CEL)

Dipl.-Ing. Martin B.
Research Associate

Kaiserstraße 12
Building 05.01
76131 Karlsruhe

Phone: +49 721 608-43790
Fax: +49 721 608-46071
www.cel.kit.edu

KIT – University of the State of Baden-Württemberg and
National Laboratory of the Helmholtz Association

4

These blocks are implemented in python.
Have a look at the following two files to start off with:
gnuradio/gr-digital/python/qam.py
gnuradio/gr-digital/python/generic_mod_demod.py

Ben

5

On 05/31/2012 09:11 AM, Martin B. wrote:

Status: inactive

I want to ping the ip address 192.168.10.2 but the response is unreachable.

I don’t think you can ping USRP2s.

Yea the fw for the old libusrp2 drivers didnt have ping.

But its fine on UHD :slight_smile:

Start here to get the driver and images:
http://code.ettus.com/redmine/ettus/projects/uhd/wiki

And the SD card instructions:
http://files.ettus.com/uhd_docs/manual/html/usrp2.html#load-the-images-onto-the-sd-card-usrp2-only

-josh

6

Hello
I want to know the IP address of USRP2. My problem is I want to use
usrp2 device with Matlab Simulink for that I need to know the Ip of the
USRP and be sure about it.
I used usrp2_recovery --ifc=eth0 --new-ip=192.168.10.2
And it says the Ip has been changed. Is there a method from which I can
verify that the IP address has been changed.

Regards,
Umer Rabbani | Researcher

Polaris House, PP129 B29, Adastral Park, Ipswich, UK
Postal Code IP5 3RE
01473645887|  - 0743 57 67 821

7

The python generic_demod.py block uses the constellation_receiver_cb
block to do both some fine-tuning of the phase and the mapping to
bits. It can be found at:
gnuradio/gr-digital/lib/digital_constellation_receiver_cb.cc
This in turn will use the decision_maker method of the constellation
object to do the mapping which can be found in:
gnuradio/gr-digital/lib/digital_constellation.cc
What exactly are you trying to do?