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Today's Topics:
1. Re: Phase Offset between USRP-B210 Channels
(Robert Kossler via USRP-users)
2. Antenna selection for B210 (ali hanif via USRP-users)
3. Re: Antenna selection for B210 (ali hanif via USRP-users)
4. Re: Antenna selection for B210 (Marcus D. Leech via USRP-users)
5. Re: Antenna selection for B210 (Marcus D. Leech via USRP-users)
6. Re: Antenna selection for B210 (Marcus D. Leech via USRP-users)
7. Re: Antenna selection for B210 (Marcus D. Leech via USRP-users)
----------------------------------------------------------------------
Message: 1
Date: Fri, 2 May 2014 11:58:39 -0400
From: Robert Kossler via USRP-users <[email protected]>
To: Stefan Ereth <[email protected]>
Cc: "[email protected]" <[email protected]>
Subject: Re: [USRP-users] Phase Offset between USRP-B210 Channels
Message-ID:
<[email protected]>
Content-Type: text/plain; charset="utf-8"
Hi Stefan,
Regarding your code, I noticed that it is streaming the 2 RX channels to file.
I have also modified some Ettus examples to do this same task (see attached).
It is based on rx_samples_to_file and benchmark_rate rather than
rx_multi_samples. One reason I chose to modify the rx_samples_to_file example
was that it included an LO Locked verification. Not sure if that could affect
your results by not doing this check...
Regarding the phase offset, is it just a calibration issue? If you measure a
phase offset with a ref signal and then later measure a real signal and apply
the cal offset, does that fix your issue?
Rob Kossler
-----Original Message-----
From: USRP-users [mailto:[email protected]] On Behalf Of
Stefan Ereth via USRP-users
Sent: Friday, May 02, 2014 2:30 AM
To: [email protected]
Subject: [USRP-users] Phase Offset between USRP-B210 Channels
Hi all,
I'm saving IQ-Samples from both Channels of an USRP B210 for Direction of
Arrival Estimation with Music. My source Code is based on the
rx_multi_samples.cpp example. For tests I connected a sine-generator with a
splitter to both channels. With a pulse sine a verified that the measured data
is time aligned. (picture abs_pulse_sine in appendix) But the problem is, that
there is a phase offset between the two channels of more than 180 degree.
(picture real_sine and phase_diff) This offset varies by retuning.
I don't understand where this phase offset come from, because the LO of both
channels is in the same Chip and should be phase aligned. Is this a known
problem of the B210? Or is there an error in my source code?
Regards,
Stefan Ereth
//
// Copyright 2011 Ettus Research LLC
//
// This program is free software: you can redistribute it and/or modify // it
under the terms of the GNU General Public License as published by // the Free
Software Foundation, either version 3 of the License, or // (at your option)
any later version.
//
// This program is distributed in the hope that it will be useful, // but
WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for
more details.
//
// You should have received a copy of the GNU General Public License // along
with this program. If not, see <http://www.gnu.org/licenses/>.
//
#define use_short
#include <uhd/utils/thread_priority.hpp> #include <uhd/utils/safe_main.hpp>
#include <uhd/usrp/multi_usrp.hpp> #include <boost/program_options.hpp>
#include <boost/format.hpp> #include <boost/thread.hpp> #include
<boost/lexical_cast.hpp> #include <boost/algorithm/string.hpp> #include
<iostream> #include <fstream> #include <complex>
namespace po = boost::program_options;
int UHD_SAFE_MAIN(int argc, char *argv[]){
uhd::set_thread_priority_safe();
//variables to be set by po
std::string args, sync, subdev, channel_list,file,file0,file1;
double seconds_in_future, freq;
size_t total_num_samps;
double rate,gain,tx_gain;
std::ofstream outfile,outfile2;
//setup the program options
po::options_description desc("Allowed options");
desc.add_options()
("help", "help message")
("args", po::value<std::string>(&args)->default_value(""), "single uhd
device address args")
("file", po::value<std::string>(&file)->default_value("measure0-1"),
"name of the file to write binary samples to")
("secs", po::value<double>(&seconds_in_future)->default_value(1.0),
"number of seconds in the future to receive")
("nsamps", po::value<size_t>(&total_num_samps)->default_value(10000),
"total number of samples to receive")
("rate", po::value<double>(&rate)->default_value(8e6), "rate of
incoming samples")
("sync", po::value<std::string>(&sync)->default_value("b210"),
"synchronization method: now, pps, mimo")
("freq", po::value<double>(&freq)->default_value(800e6), "RF center
frequency in Hz")
("gain", po::value<double>(&gain), "gain for the RF chain")
("tx-gain", po::value<double>(&tx_gain), "gain for the TX in
calibration Mode")
("subdev", po::value<std::string>(&subdev), "subdev spec (homogeneous
across motherboards)")
("v", "specify to enable inner-loop verbose")
("calc","specify to enable transmitting and recording of calibration
data")
("channels", po::value<std::string>(&channel_list)->default_value("0"),
"which channel(s) to use (specify \"0\", \"1\", \"0,1\", etc)")
;
po::variables_map vm;
po::store(po::parse_command_line(argc, argv, desc), vm);
po::notify(vm);
//print the help message
if (vm.count("help")){
std::cout << boost::format("UHD RX Multi Samples %s") % desc <<
std::endl;
std::cout <<
" This is a demonstration of how to receive aligned data from
multiple channels.\n"
" This example can receive from multiple DSPs, multiple
motherboards, or both.\n"
" The MIMO cable or PPS can be used to synchronize the
configuration. See --sync\n"
"\n"
" Specify --subdev to select multiple channels per motherboard.\n"
" Ex: --subdev=\"0:A 0:B\" to get 2 channels on a Basic RX.\n"
"\n"
" Specify --args to select multiple motherboards in a
configuration.\n"
" Ex: --args=\"addr0=192.168.10.2, addr1=192.168.10.3\"\n"
<< std::endl;
return ~0;
}
bool verbose = vm.count("v") == 1;
bool calibration = vm.count("calc") == 1;
/**************** RX Init *************************************************/
//create a usrp device
std::cout << std::endl;
std::cout << boost::format("Creating the usrp device with: %s...") % args
<< std::endl;
uhd::usrp::multi_usrp::sptr usrp = uhd::usrp::multi_usrp::make(args);
usrp->set_master_clock_rate(30e6); //less then 30.72e6 //M?glichkeit 1:
Variable Clock-Rate
//always select the subdevice first, the channel mapping affects the other
settings
if (vm.count("subdev")){
uhd::usrp::subdev_spec_t subdevClass = subdev;
std::cout << subdevClass.to_pp_string() << std::endl;
usrp->set_rx_subdev_spec(subdevClass); //sets across all mboards
}
std::cout << boost::format("Using Device: %s") % usrp->get_pp_string() <<
std::endl;
//set the rx sample rate (sets across all channels)
std::cout << boost::format("Setting RX Rate: %f Msps... ") % (rate/1e6) <<
std::endl;
usrp->set_rx_rate(rate);
std::cout << boost::format("Actual RX Rate: %f Msps...") %
(usrp->get_rx_rate()/1e6) << std::endl << std::endl;
//set center Frequency
std::cout << boost::format("Setting RX Freq: %f MHz...") % (freq/1e6) <<
std::endl;
uhd::tune_request_t tune_request(freq);
for(size_t i=0;i<usrp->get_rx_num_channels();i++)
usrp->set_rx_freq(tune_request,i);
std::cout << boost::format("Actual RX Freq: %f MHz...") %
(usrp->get_rx_freq(1)/1e6) << std::endl << std::endl;
//set the rf gain
if (vm.count("gain")){
for(size_t i=0;i<usrp->get_rx_num_channels();i++){
std::cout << boost::format("Setting RX Gain for Channel %d: %f
dB...") % i % gain << std::endl;
usrp->set_rx_gain(gain,i);
std::cout << boost::format("Actual RX Gain: %f dB...") %
usrp->get_rx_gain() << std::endl << std::endl;
}
}
//open files to write
if(calibration) file+=".calc"; //Kalibrierdaten mit Endung .calc
else file+=".dat"; //Messdaten mit Endung.dat
file0 = file;
file1 = file;
file0 += "0";
file1 += "1";
outfile.open(file0.c_str(), std::ofstream::binary);
if(usrp->get_rx_num_channels()>1){
outfile2.open(file1.c_str(),std::ofstream::binary);
}
/**************** Recieve Start ******************************************/
//create a receive streamer
//linearly map channels (index0 = channel0, index1 = channel1, ...)
uhd::stream_args_t stream_args("sc16"); //complex short
//stream_args.channels = channel_nums;
for (size_t i = 0; i < usrp->get_rx_num_channels(); i++)
stream_args.channels.push_back(i);
uhd::rx_streamer::sptr rx_stream = usrp->get_rx_stream(stream_args);
//setup streaming
std::cout << std::endl;
std::cout << boost::format(
"Begin receiving of %u samples. Start in %f seconds in the future..."
) % total_num_samps % seconds_in_future << std::endl;
uhd::stream_cmd_t
stream_cmd(uhd::stream_cmd_t::STREAM_MODE_NUM_SAMPS_AND_DONE);
stream_cmd.num_samps = total_num_samps;
stream_cmd.stream_now = false;
stream_cmd.time_spec = uhd::time_spec_t(seconds_in_future) +
usrp->get_time_now();
rx_stream->issue_stream_cmd(stream_cmd); //tells all channels to stream
//meta-data will be filled in by recv()
uhd::rx_metadata_t md;
//allocate buffers to receive with samples (one buffer per channel)
const size_t samps_per_buff = rx_stream->get_max_num_samps();
std::vector<std::vector<std::complex<short> > > buffs(
usrp->get_rx_num_channels(), std::vector<std::complex<short>
>(samps_per_buff)
);
//create a vector of pointers to point to each of the channel buffers
std::vector<std::complex<short> *> buff_ptrs;
for (size_t i = 0; i < buffs.size(); i++)
buff_ptrs.push_back(&buffs[i].front());
//the first call to recv() will block this many seconds before receiving
double timeout = seconds_in_future + 1; //timeout (delay before receive +
padding)
size_t num_acc_samps = 0; //number of accumulated samples
while(num_acc_samps < total_num_samps){
//receive a single packet
size_t num_rx_samps = rx_stream->recv(
buff_ptrs, samps_per_buff, md, timeout
);
//use a small timeout for subsequent packets
timeout = 0.1;
//handle the error code
if (md.error_code == uhd::rx_metadata_t::ERROR_CODE_TIMEOUT) break;
if (md.error_code != uhd::rx_metadata_t::ERROR_CODE_NONE){
throw std::runtime_error(str(boost::format(
"Receiver error %s"
) % md.strerror()));
}
if(verbose) std::cout << boost::format(
"Received packet: %u samples, %u full secs, %f frac secs"
) % num_rx_samps % md.time_spec.get_full_secs() %
md.time_spec.get_frac_secs() << std::endl;
//Schreiben der gelesenen Werte in die Dateien
if(outfile.is_open())
outfile.write((const char
*)&buffs[0].front(),num_rx_samps*sizeof(buffs[0].front()));
if(outfile2.is_open())
outfile2.write((const char
*)&buffs[1].front(),num_rx_samps*sizeof(buffs[1][0]));
num_acc_samps += num_rx_samps;
}
if (num_acc_samps < total_num_samps) std::cerr << "Receive timeout before
all samples received..." << std::endl;
/**************************** Recieve End
*******************************************************/
if(outfile.is_open())
outfile.close();
if(outfile2.is_open())
outfile2.close();
//finished
std::cout << std::endl << "Done! Mine" << std::endl << std::endl;
return EXIT_SUCCESS;
}
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Message: 2
Date: Fri, 2 May 2014 23:44:01 +0500
From: ali hanif via USRP-users <[email protected]>
To: "[email protected]" <[email protected]>
Subject: [USRP-users] Antenna selection for B210
Message-ID:
<caejvf3tsmn3kqphzfz5e_8my2z_4l2fxvxpl-_dfmahzudn...@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"
Hi,
I am using B210 in a project related to DRFM..which is the best antenna to
use?
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Message: 3
Date: Fri, 2 May 2014 23:50:49 +0500
From: ali hanif via USRP-users <[email protected]>
To: "[email protected]" <[email protected]>
Subject: Re: [USRP-users] Antenna selection for B210
Message-ID:
<CAEjvF3TTBJ9uj-8SAUvTeerXRR6boNd=gl12_quq+yb0wqx...@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"
The operating frequency is 2.4-2.5GHz
On Fri, May 2, 2014 at 11:44 PM, ali hanif <[email protected]> wrote:
> Hi,
> I am using B210 in a project related to DRFM..which is the best antenna to
> use?
>
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Message: 4
Date: Fri, 02 May 2014 15:07:34 -0400
From: "Marcus D. Leech via USRP-users" <[email protected]>
To: ali hanif <[email protected]>, "[email protected]"
<[email protected]>
Subject: Re: [USRP-users] Antenna selection for B210
Message-ID: <[email protected]>
Content-Type: text/plain; charset="utf-8"; Format="flowed"
On 05/02/2014 03:04 PM, ali hanif wrote:
> no i need omni directional and vertically polarized with nice gain
>
>
Truly omnidirectional antennae have unity gain.
There are things like colinear array antennas that have a "pancake" pattern.
This would probably work:
https://www.ettus.com/product/details/VERT2450
> On Fri, May 2, 2014 at 11:59 PM, Marcus D. Leech <[email protected]
> <mailto:[email protected]>> wrote:
>
> On 05/02/2014 02:50 PM, ali hanif via USRP-users wrote:
>> The operating frequency is 2.4-2.5GHz
>>
>>
>> On Fri, May 2, 2014 at 11:44 PM, ali hanif <[email protected]
>> <mailto:[email protected]>> wrote:
>>
>> Hi,
>> I am using B210 in a project related to DRFM..which is the
>> best antenna to use?
>>
>>
>>
>>
>> _______________________________________________
>> USRP-users mailing list
>> [email protected] <mailto:[email protected]>
>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
> Do you need directionality?
>
> There are a huge number of antenna types out there, Ettus sells a
> tiny fraction of what's available, to cover the most common use
> cases.
>
>
>
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Message: 5
Date: Fri, 02 May 2014 15:20:41 -0400
From: "Marcus D. Leech via USRP-users" <[email protected]>
To: ali hanif <[email protected]>, "[email protected]"
<[email protected]>
Subject: Re: [USRP-users] Antenna selection for B210
Message-ID: <[email protected]>
Content-Type: text/plain; charset="utf-8"; Format="flowed"
On 05/02/2014 03:14 PM, ali hanif wrote:
> Yes but it has 3dBi gain..isotropic antenna has unity gain i think
>
>
Yes, it probably has a slightly-squashed pattern.
There's no such thing, in reality, as a purely-isotropic antenna. They
are theoretical constructs only.
> On Sat, May 3, 2014 at 12:07 AM, Marcus D. Leech <[email protected]
> <mailto:[email protected]>> wrote:
>
> On 05/02/2014 03:04 PM, ali hanif wrote:
>> no i need omni directional and vertically polarized with nice gain
>>
>>
> Truly omnidirectional antennae have unity gain.
>
> There are things like colinear array antennas that have a
> "pancake" pattern.
>
> This would probably work:
>
> https://www.ettus.com/product/details/VERT2450
>
>
>
>> On Fri, May 2, 2014 at 11:59 PM, Marcus D. Leech
>> <[email protected] <mailto:[email protected]>> wrote:
>>
>> On 05/02/2014 02:50 PM, ali hanif via USRP-users wrote:
>>> The operating frequency is 2.4-2.5GHz
>>>
>>>
>>> On Fri, May 2, 2014 at 11:44 PM, ali hanif
>>> <[email protected] <mailto:[email protected]>> wrote:
>>>
>>> Hi,
>>> I am using B210 in a project related to DRFM..which is
>>> the best antenna to use?
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> USRP-users mailing list
>>> [email protected] <mailto:[email protected]>
>>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>> Do you need directionality?
>>
>> There are a huge number of antenna types out there, Ettus
>> sells a tiny fraction of what's available, to cover the most
>> common use
>> cases.
>>
>>
>>
>
>
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Message: 6
Date: Fri, 02 May 2014 15:38:04 -0400
From: "Marcus D. Leech via USRP-users" <[email protected]>
To: ali hanif <[email protected]>, "[email protected]"
<[email protected]>
Subject: Re: [USRP-users] Antenna selection for B210
Message-ID: <[email protected]>
Content-Type: text/plain; charset=UTF-8; format=flowed
On 05/02/2014 03:23 PM, ali hanif wrote:
> Gain only increases the range of operation and directivity...does the
> output power in that direction also increases??
>
Consider a uniformly isotropic radiator. The power introduced into it
is radiated away uniformly in all directions.
For a non-uniform radiator (that is, one that has some amount of
directionality, and thus "gain"), the power radiated in some directions is
more than others.
------------------------------
Message: 7
Date: Fri, 02 May 2014 15:47:25 -0400
From: "Marcus D. Leech via USRP-users" <[email protected]>
To: ali hanif <[email protected]>, "[email protected]"
<[email protected]>
Subject: Re: [USRP-users] Antenna selection for B210
Message-ID: <[email protected]>
Content-Type: text/plain; charset="utf-8"; Format="flowed"
On 05/02/2014 03:44 PM, ali hanif wrote:
> yes but it will be less than the power supplied to the antenna as it
> is a passive device?
>
>
Yes, "gain" when applied to passive-antenna structures is a way of
expressing their directionality as a simple magnitude, but the "full story"
involves looking at the antenna pattern in 3-space.
For example, a YAGI is generally rated in terms of its "forward gain",
that is the amount of injected power that is radiated in the notionally
"forward" direction of the antenna.
> On Sat, May 3, 2014 at 12:38 AM, Marcus D. Leech <[email protected]
> <mailto:[email protected]>> wrote:
>
> On 05/02/2014 03:23 PM, ali hanif wrote:
>
> Gain only increases the range of operation and
> directivity...does the output power in that direction also
> increases??
>
> Consider a uniformly isotropic radiator. The power introduced
> into it is radiated away uniformly in all directions.
>
> For a non-uniform radiator (that is, one that has some amount of
> directionality, and thus "gain"), the power radiated in some
> directions is
> more than others.
>
>
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