SS
siva sankar
Thu, Apr 23, 2015 10:28 AM
Hello List,
I am using USRP B210 and the UHD version is 003.008.000. We are
transmitting on one channel and receiving simultaneously on both the
channels and what we want is the time of arrival of the first sample in
both the receive buffers.
We have used the "time_spec_t" to get the time of the first sample but we
don't know if the time that we are getting is for both the channels or for
one of the receiver buffers.
We have tried using two "recv" commands one for each buffer hoping we could
calculate the time from each metadata parameter passed to the "recv"
command in one thread but it throws "multi channel alignment" error and
stops running.
We also tried to create individual threads for both the rx channels and
pass different metadata parameters and hence know the time of first sample
for each buffer. However, this throws segmentation fault.
Any help on how to calculate the time of first sample for each receive
buffer will be appreciated.
Thanks
Siva.
Hello List,
I am using USRP B210 and the UHD version is 003.008.000. We are
transmitting on one channel and receiving simultaneously on both the
channels and what we want is the time of arrival of the first sample in
both the receive buffers.
We have used the "time_spec_t" to get the time of the first sample but we
don't know if the time that we are getting is for both the channels or for
one of the receiver buffers.
We have tried using two "recv" commands one for each buffer hoping we could
calculate the time from each metadata parameter passed to the "recv"
command in one thread but it throws "multi channel alignment" error and
stops running.
We also tried to create individual threads for both the rx channels and
pass different metadata parameters and hence know the time of first sample
for each buffer. However, this throws segmentation fault.
Any help on how to calculate the time of first sample for each receive
buffer will be appreciated.
Thanks
Siva.
MM
Marcus Müller
Thu, Apr 23, 2015 10:55 AM
Hello Siva,
recv() will do an aligned reception, i.e. the first samples of both
streams were received at the same time.
Often, you don't want to /know/ /afterwards/ the time of reception, you
want to /define/ it beforehand. You can do that by using a stream_cmd
with a stream_now = false and a timespec to allow you to define when the
reception is going to take place.
Greetings,
Marcus
On 04/23/2015 12:28 PM, siva sankar via USRP-users wrote:
Hello List,
I am using USRP B210 and the UHD version is 003.008.000. We are
transmitting on one channel and receiving simultaneously on both the
channels and what we want is the time of arrival of the first sample
in both the receive buffers.
We have used the "time_spec_t" to get the time of the first sample but
we don't know if the time that we are getting is for both the channels
or for one of the receiver buffers.
We have tried using two "recv" commands one for each buffer hoping we
could calculate the time from each metadata parameter passed to the
"recv" command in one thread but it throws "multi channel alignment"
error and stops running.
We also tried to create individual threads for both the rx channels
and pass different metadata parameters and hence know the time of
first sample for each buffer. However, this throws segmentation fault.
Any help on how to calculate the time of first sample for each receive
buffer will be appreciated.
Thanks
Siva.
USRP-users mailing list
USRP-users@lists.ettus.com
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
Hello Siva,
recv() will do an aligned reception, i.e. the first samples of both
streams were received at the same time.
Often, you don't want to /know/ /afterwards/ the time of reception, you
want to /define/ it beforehand. You can do that by using a stream_cmd
with a stream_now = false and a timespec to allow you to define when the
reception is going to take place.
Greetings,
Marcus
On 04/23/2015 12:28 PM, siva sankar via USRP-users wrote:
> Hello List,
>
> I am using USRP B210 and the UHD version is 003.008.000. We are
> transmitting on one channel and receiving simultaneously on both the
> channels and what we want is the time of arrival of the first sample
> in both the receive buffers.
>
> We have used the "time_spec_t" to get the time of the first sample but
> we don't know if the time that we are getting is for both the channels
> or for one of the receiver buffers.
>
> We have tried using two "recv" commands one for each buffer hoping we
> could calculate the time from each metadata parameter passed to the
> "recv" command in one thread but it throws "multi channel alignment"
> error and stops running.
>
> We also tried to create individual threads for both the rx channels
> and pass different metadata parameters and hence know the time of
> first sample for each buffer. However, this throws segmentation fault.
>
> Any help on how to calculate the time of first sample for each receive
> buffer will be appreciated.
>
> Thanks
> Siva.
>
>
> _______________________________________________
> USRP-users mailing list
> USRP-users@lists.ettus.com
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
SS
siva sankar
Thu, Apr 23, 2015 12:53 PM
Hey Marcus,
Thanks for the reply.
The receivers here are at different distances from the transmitter and we
are looking for the time difference of arrival of the samples at the
receive buffers.
How do we proceed with this ?
Regards
Siva
Hello Siva,
recv() will do an aligned reception, i.e. the first samples of both streams
were received at the same time.
Often, you don't want to know afterwards the time of reception, you
want to define it beforehand. You can do that by using a stream_cmd with
a stream_now = false and a timespec to allow you to define when the
reception is going to take place.
Greetings,
Marcus
On 04/23/2015 12:28 PM, siva sankar via USRP-users wrote:
Hello List,
I am using USRP B210 and the UHD version is 003.008.000. We are
transmitting on one channel and receiving simultaneously on both the
channels and what we want is the time of arrival of the first sample in
both the receive buffers.
We have used the "time_spec_t" to get the time of the first sample but we
don't know if the time that we are getting is for both the channels or for
one of the receiver buffers.
We have tried using two "recv" commands one for each buffer hoping we
could calculate the time from each metadata parameter passed to the "recv"
command in one thread but it throws "multi channel alignment" error and
stops running.
We also tried to create individual threads for both the rx channels and
pass different metadata parameters and hence know the time of first sample
for each buffer. However, this throws segmentation fault.
Any help on how to calculate the time of first sample for each receive
buffer will be appreciated.
Thanks
Siva.
USRP-users mailing
listUSRP-users@lists.ettus.comhttp://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
USRP-users mailing list
USRP-users@lists.ettus.com
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
Hey Marcus,
Thanks for the reply.
The receivers here are at different distances from the transmitter and we
are looking for the time difference of arrival of the samples at the
receive buffers.
How do we proceed with this ?
Regards
Siva
Hello Siva,
recv() will do an aligned reception, i.e. the first samples of both streams
were received at the same time.
Often, you don't want to *know* *afterwards* the time of reception, you
want to *define* it beforehand. You can do that by using a stream_cmd with
a stream_now = false and a timespec to allow you to define when the
reception is going to take place.
Greetings,
Marcus
On 04/23/2015 12:28 PM, siva sankar via USRP-users wrote:
Hello List,
I am using USRP B210 and the UHD version is 003.008.000. We are
transmitting on one channel and receiving simultaneously on both the
channels and what we want is the time of arrival of the first sample in
both the receive buffers.
We have used the "time_spec_t" to get the time of the first sample but we
don't know if the time that we are getting is for both the channels or for
one of the receiver buffers.
We have tried using two "recv" commands one for each buffer hoping we
could calculate the time from each metadata parameter passed to the "recv"
command in one thread but it throws "multi channel alignment" error and
stops running.
We also tried to create individual threads for both the rx channels and
pass different metadata parameters and hence know the time of first sample
for each buffer. However, this throws segmentation fault.
Any help on how to calculate the time of first sample for each receive
buffer will be appreciated.
Thanks
Siva.
_______________________________________________
USRP-users mailing
listUSRP-users@lists.ettus.comhttp://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
_______________________________________________
USRP-users mailing list
USRP-users@lists.ettus.com
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
MM
Marcus Müller
Thu, Apr 23, 2015 12:55 PM
Hey Siva,
I assume this means you have two B210s?
Sorry, I don't really have a picture of your setup in mind, would you
mind making a sketch?
Best regards,
Marcus
On 04/23/2015 02:53 PM, siva sankar wrote:
Hey Marcus,
Thanks for the reply.
The receivers here are at different distances from the transmitter and
we are looking for the time difference of arrival of the samples at
the receive buffers.
How do we proceed with this ?
Regards
Siva
Hello Siva,
recv() will do an aligned reception, i.e. the first samples of both
streams were received at the same time.
Often, you don't want to /know/ /afterwards/ the time of reception,
you want to /define/ it beforehand. You can do that by using a
stream_cmd with a stream_now = false and a timespec to allow you to
define when the reception is going to take place.
Greetings,
Marcus
On 04/23/2015 12:28 PM, siva sankar via USRP-users wrote:
Hello List,
I am using USRP B210 and the UHD version is 003.008.000. We are
transmitting on one channel and receiving simultaneously on both the
channels and what we want is the time of arrival of the first sample
in both the receive buffers.
We have used the "time_spec_t" to get the time of the first sample
but we don't know if the time that we are getting is for both the
channels or for one of the receiver buffers.
We have tried using two "recv" commands one for each buffer hoping we
could calculate the time from each metadata parameter passed to the
"recv" command in one thread but it throws "multi channel alignment"
error and stops running.
We also tried to create individual threads for both the rx channels
and pass different metadata parameters and hence know the time of
first sample for each buffer. However, this throws segmentation fault.
Any help on how to calculate the time of first sample for each
receive buffer will be appreciated.
Thanks
Siva.
USRP-users mailing list
USRP-users@lists.ettus.com mailto:USRP-users@lists.ettus.com
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
Hey Siva,
I assume this means you have two B210s?
Sorry, I don't really have a picture of your setup in mind, would you
mind making a sketch?
Best regards,
Marcus
On 04/23/2015 02:53 PM, siva sankar wrote:
>
> Hey Marcus,
>
> Thanks for the reply.
> The receivers here are at different distances from the transmitter and
> we are looking for the time difference of arrival of the samples at
> the receive buffers.
>
> How do we proceed with this ?
>
> Regards
> Siva
>
> Hello Siva,
> recv() will do an aligned reception, i.e. the first samples of both
> streams were received at the same time.
>
> Often, you don't want to /know/ /afterwards/ the time of reception,
> you want to /define/ it beforehand. You can do that by using a
> stream_cmd with a stream_now = false and a timespec to allow you to
> define when the reception is going to take place.
>
> Greetings,
> Marcus
>
>
> On 04/23/2015 12:28 PM, siva sankar via USRP-users wrote:
>> Hello List,
>>
>> I am using USRP B210 and the UHD version is 003.008.000. We are
>> transmitting on one channel and receiving simultaneously on both the
>> channels and what we want is the time of arrival of the first sample
>> in both the receive buffers.
>>
>> We have used the "time_spec_t" to get the time of the first sample
>> but we don't know if the time that we are getting is for both the
>> channels or for one of the receiver buffers.
>>
>> We have tried using two "recv" commands one for each buffer hoping we
>> could calculate the time from each metadata parameter passed to the
>> "recv" command in one thread but it throws "multi channel alignment"
>> error and stops running.
>>
>> We also tried to create individual threads for both the rx channels
>> and pass different metadata parameters and hence know the time of
>> first sample for each buffer. However, this throws segmentation fault.
>>
>> Any help on how to calculate the time of first sample for each
>> receive buffer will be appreciated.
>>
>> Thanks
>> Siva.
>>
>>
>> _______________________________________________
>> USRP-users mailing list
>> USRP-users@lists.ettus.com <mailto:USRP-users@lists.ettus.com>
>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>
>
> _______________________________________________
> USRP-users mailing list
> USRP-users@lists.ettus.com <mailto:USRP-users@lists.ettus.com>
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>
LL
LOUF Laurent
Thu, Apr 23, 2015 2:08 PM
Hi,
If you just want the time difference, you may want to compute the correlation between the two signals for different offsets (unit : samples) and find the offset that gives you the maximum of correlation (and then translate the number of samples into a time difference with the sampling frequency). If receivers are not too far away one from the other, I guess that could be a solution (to be investigated).
Regards,
Laurent.
De : USRP-users [mailto:usrp-users-bounces@lists.ettus.com] De la part de siva sankar via USRP-users
Envoyé : jeudi 23 avril 2015 14:54
À : Marcus Müller
Cc : usrp-users@lists.ettus.com
Objet : Re: [USRP-users] Time of arrival of first sample in a 2 Rx setup
Hey Marcus,
Thanks for the reply.
The receivers here are at different distances from the transmitter and we are looking for the time difference of arrival of the samples at the receive buffers.
How do we proceed with this ?
Regards
Siva
Hello Siva,
recv() will do an aligned reception, i.e. the first samples of both streams were received at the same time.
Often, you don't want to know afterwards the time of reception, you want to define it beforehand. You can do that by using a stream_cmd with a stream_now = false and a timespec to allow you to define when the reception is going to take place.
Greetings,
Marcus
On 04/23/2015 12:28 PM, siva sankar via USRP-users wrote:
Hello List,
I am using USRP B210 and the UHD version is 003.008.000. We are transmitting on one channel and receiving simultaneously on both the channels and what we want is the time of arrival of the first sample in both the receive buffers.
We have used the "time_spec_t" to get the time of the first sample but we don't know if the time that we are getting is for both the channels or for one of the receiver buffers.
We have tried using two "recv" commands one for each buffer hoping we could calculate the time from each metadata parameter passed to the "recv" command in one thread but it throws "multi channel alignment" error and stops running.
We also tried to create individual threads for both the rx channels and pass different metadata parameters and hence know the time of first sample for each buffer. However, this throws segmentation fault.
Any help on how to calculate the time of first sample for each receive buffer will be appreciated.
Thanks
Siva.
USRP-users mailing list
USRP-users@lists.ettus.commailto:USRP-users@lists.ettus.com
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
USRP-users mailing list
USRP-users@lists.ettus.commailto:USRP-users@lists.ettus.com
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
Hi,
If you just want the time difference, you may want to compute the correlation between the two signals for different offsets (unit : samples) and find the offset that gives you the maximum of correlation (and then translate the number of samples into a time difference with the sampling frequency). If receivers are not too far away one from the other, I guess that could be a solution (to be investigated).
Regards,
Laurent.
De : USRP-users [mailto:usrp-users-bounces@lists.ettus.com] De la part de siva sankar via USRP-users
Envoyé : jeudi 23 avril 2015 14:54
À : Marcus Müller
Cc : usrp-users@lists.ettus.com
Objet : Re: [USRP-users] Time of arrival of first sample in a 2 Rx setup
Hey Marcus,
Thanks for the reply.
The receivers here are at different distances from the transmitter and we are looking for the time difference of arrival of the samples at the receive buffers.
How do we proceed with this ?
Regards
Siva
Hello Siva,
recv() will do an aligned reception, i.e. the first samples of both streams were received at the same time.
Often, you don't want to know afterwards the time of reception, you want to define it beforehand. You can do that by using a stream_cmd with a stream_now = false and a timespec to allow you to define when the reception is going to take place.
Greetings,
Marcus
On 04/23/2015 12:28 PM, siva sankar via USRP-users wrote:
Hello List,
I am using USRP B210 and the UHD version is 003.008.000. We are transmitting on one channel and receiving simultaneously on both the channels and what we want is the time of arrival of the first sample in both the receive buffers.
We have used the "time_spec_t" to get the time of the first sample but we don't know if the time that we are getting is for both the channels or for one of the receiver buffers.
We have tried using two "recv" commands one for each buffer hoping we could calculate the time from each metadata parameter passed to the "recv" command in one thread but it throws "multi channel alignment" error and stops running.
We also tried to create individual threads for both the rx channels and pass different metadata parameters and hence know the time of first sample for each buffer. However, this throws segmentation fault.
Any help on how to calculate the time of first sample for each receive buffer will be appreciated.
Thanks
Siva.
_______________________________________________
USRP-users mailing list
USRP-users@lists.ettus.com<mailto:USRP-users@lists.ettus.com>
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
_______________________________________________
USRP-users mailing list
USRP-users@lists.ettus.com<mailto:USRP-users@lists.ettus.com>
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
SS
siva sankar
Fri, Apr 24, 2015 5:45 AM
Hey Marcus,
I am attaching the picture of the set up. The two receivers(Receiver 1 and
Receiver 2) shown in the picture are on one USRP B210. We are trying to
calculate the angle of arrival using the TDOA.
These are the equations being used:
Sin θ= S/L;
S = (TDOA)*Speed of light(C);
θ=arcsin(((TDOA)*C)/L);
On Thu, Apr 23, 2015 at 7:38 PM, LOUF Laurent laurent.louf@thalesgroup.com
wrote:
Hi,
If you just want the time difference, you may want to compute the
correlation between the two signals for different offsets (unit : samples)
and find the offset that gives you the maximum of correlation (and then
translate the number of samples into a time difference with the sampling
frequency). If receivers are not too far away one from the other, I guess
that could be a solution (to be investigated).
Regards,
Laurent.
De : USRP-users [mailto:usrp-users-bounces@lists.ettus.com] De la part
de siva sankar via USRP-users
Envoyé : jeudi 23 avril 2015 14:54
À : Marcus Müller
Cc : usrp-users@lists.ettus.com
Objet : Re: [USRP-users] Time of arrival of first sample in a 2 Rx setup
Hey Marcus,
Thanks for the reply.
The receivers here are at different distances from the transmitter and we
are looking for the time difference of arrival of the samples at the
receive buffers.
How do we proceed with this ?
Regards
Siva
Hello Siva,
recv() will do an aligned reception, i.e. the first samples of both
streams were received at the same time.
Often, you don't want to know afterwards the time of reception, you
want to define it beforehand. You can do that by using a stream_cmd
with a stream_now = false and a timespec to allow you to define when the
reception is going to take place.
Greetings,
Marcus
On 04/23/2015 12:28 PM, siva sankar via USRP-users wrote:
Hello List,
I am using USRP B210 and the UHD version is 003.008.000. We are
transmitting on one channel and receiving simultaneously on both the
channels and what we want is the time of arrival of the first sample in
both the receive buffers.
We have used the "time_spec_t" to get the time of the first sample but we
don't know if the time that we are getting is for both the channels or for
one of the receiver buffers.
We have tried using two "recv" commands one for each buffer hoping we
could calculate the time from each metadata parameter passed to the "recv"
command in one thread but it throws "multi channel alignment" error and
stops running.
We also tried to create individual threads for both the rx channels and
pass different metadata parameters and hence know the time of first sample
for each buffer. However, this throws segmentation fault.
Any help on how to calculate the time of first sample for each receive
buffer will be appreciated.
Thanks
Siva.
USRP-users mailing list
USRP-users@lists.ettus.com
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
USRP-users mailing list
USRP-users@lists.ettus.com
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
--
Thanks and regards
Siva Sankar.
Hey Marcus,
I am attaching the picture of the set up. The two receivers(Receiver 1 and
Receiver 2) shown in the picture are on one USRP B210. We are trying to
calculate the angle of arrival using the TDOA.
These are the equations being used:
Sin θ= S/L;
S = (TDOA)*Speed of light(C);
θ=arcsin(((TDOA)*C)/L);
On Thu, Apr 23, 2015 at 7:38 PM, LOUF Laurent <laurent.louf@thalesgroup.com>
wrote:
> Hi,
>
>
>
> If you just want the time difference, you may want to compute the
> correlation between the two signals for different offsets (unit : samples)
> and find the offset that gives you the maximum of correlation (and then
> translate the number of samples into a time difference with the sampling
> frequency). If receivers are not too far away one from the other, I guess
> that could be a solution (to be investigated).
>
>
>
> Regards,
>
> Laurent.
>
>
>
>
>
> *De :* USRP-users [mailto:usrp-users-bounces@lists.ettus.com] *De la part
> de* siva sankar via USRP-users
> *Envoyé :* jeudi 23 avril 2015 14:54
> *À :* Marcus Müller
> *Cc :* usrp-users@lists.ettus.com
> *Objet :* Re: [USRP-users] Time of arrival of first sample in a 2 Rx setup
>
>
>
> Hey Marcus,
>
> Thanks for the reply.
> The receivers here are at different distances from the transmitter and we
> are looking for the time difference of arrival of the samples at the
> receive buffers.
>
> How do we proceed with this ?
>
> Regards
> Siva
>
> Hello Siva,
> recv() will do an aligned reception, i.e. the first samples of both
> streams were received at the same time.
>
> Often, you don't want to *know* *afterwards* the time of reception, you
> want to *define* it beforehand. You can do that by using a stream_cmd
> with a stream_now = false and a timespec to allow you to define when the
> reception is going to take place.
>
> Greetings,
> Marcus
>
> On 04/23/2015 12:28 PM, siva sankar via USRP-users wrote:
>
> Hello List,
>
>
>
> I am using USRP B210 and the UHD version is 003.008.000. We are
> transmitting on one channel and receiving simultaneously on both the
> channels and what we want is the time of arrival of the first sample in
> both the receive buffers.
>
>
>
> We have used the "time_spec_t" to get the time of the first sample but we
> don't know if the time that we are getting is for both the channels or for
> one of the receiver buffers.
>
>
>
> We have tried using two "recv" commands one for each buffer hoping we
> could calculate the time from each metadata parameter passed to the "recv"
> command in one thread but it throws "multi channel alignment" error and
> stops running.
>
>
>
> We also tried to create individual threads for both the rx channels and
> pass different metadata parameters and hence know the time of first sample
> for each buffer. However, this throws segmentation fault.
>
>
>
> Any help on how to calculate the time of first sample for each receive
> buffer will be appreciated.
>
>
>
> Thanks
>
> Siva.
>
>
>
> _______________________________________________
>
> USRP-users mailing list
>
> USRP-users@lists.ettus.com
>
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>
>
>
>
> _______________________________________________
> USRP-users mailing list
> USRP-users@lists.ettus.com
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>
--
Thanks and regards
Siva Sankar.
SS
siva sankar
Fri, Apr 24, 2015 6:00 AM
Hey Laurent,
Thanks for the suggestion infact this is what we initially tried to do but
we are not able to give the offset as we require high sampling rate which
on giving is throwing a sequence of L's(LLLLLLL...) .
Regards
Siva.
On Thu, Apr 23, 2015 at 7:38 PM, LOUF Laurent laurent.louf@thalesgroup.com
wrote:
Hi,
If you just want the time difference, you may want to compute the
correlation between the two signals for different offsets (unit : samples)
and find the offset that gives you the maximum of correlation (and then
translate the number of samples into a time difference with the sampling
frequency). If receivers are not too far away one from the other, I guess
that could be a solution (to be investigated).
Regards,
Laurent.
De : USRP-users [mailto:usrp-users-bounces@lists.ettus.com] De la part
de siva sankar via USRP-users
Envoyé : jeudi 23 avril 2015 14:54
À : Marcus Müller
Cc : usrp-users@lists.ettus.com
Objet : Re: [USRP-users] Time of arrival of first sample in a 2 Rx setup
Hey Marcus,
Thanks for the reply.
The receivers here are at different distances from the transmitter and we
are looking for the time difference of arrival of the samples at the
receive buffers.
How do we proceed with this ?
Regards
Siva
Hello Siva,
recv() will do an aligned reception, i.e. the first samples of both
streams were received at the same time.
Often, you don't want to know afterwards the time of reception, you
want to define it beforehand. You can do that by using a stream_cmd
with a stream_now = false and a timespec to allow you to define when the
reception is going to take place.
Greetings,
Marcus
On 04/23/2015 12:28 PM, siva sankar via USRP-users wrote:
Hello List,
I am using USRP B210 and the UHD version is 003.008.000. We are
transmitting on one channel and receiving simultaneously on both the
channels and what we want is the time of arrival of the first sample in
both the receive buffers.
We have used the "time_spec_t" to get the time of the first sample but we
don't know if the time that we are getting is for both the channels or for
one of the receiver buffers.
We have tried using two "recv" commands one for each buffer hoping we
could calculate the time from each metadata parameter passed to the "recv"
command in one thread but it throws "multi channel alignment" error and
stops running.
We also tried to create individual threads for both the rx channels and
pass different metadata parameters and hence know the time of first sample
for each buffer. However, this throws segmentation fault.
Any help on how to calculate the time of first sample for each receive
buffer will be appreciated.
Thanks
Siva.
USRP-users mailing list
USRP-users@lists.ettus.com
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
USRP-users mailing list
USRP-users@lists.ettus.com
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
--
Thanks and regards
Siva Sankar.
Hey Laurent,
Thanks for the suggestion infact this is what we initially tried to do but
we are not able to give the offset as we require high sampling rate which
on giving is throwing a sequence of L's(LLLLLLL...) .
Regards
Siva.
On Thu, Apr 23, 2015 at 7:38 PM, LOUF Laurent <laurent.louf@thalesgroup.com>
wrote:
> Hi,
>
>
>
> If you just want the time difference, you may want to compute the
> correlation between the two signals for different offsets (unit : samples)
> and find the offset that gives you the maximum of correlation (and then
> translate the number of samples into a time difference with the sampling
> frequency). If receivers are not too far away one from the other, I guess
> that could be a solution (to be investigated).
>
>
>
> Regards,
>
> Laurent.
>
>
>
>
>
> *De :* USRP-users [mailto:usrp-users-bounces@lists.ettus.com] *De la part
> de* siva sankar via USRP-users
> *Envoyé :* jeudi 23 avril 2015 14:54
> *À :* Marcus Müller
> *Cc :* usrp-users@lists.ettus.com
> *Objet :* Re: [USRP-users] Time of arrival of first sample in a 2 Rx setup
>
>
>
> Hey Marcus,
>
> Thanks for the reply.
> The receivers here are at different distances from the transmitter and we
> are looking for the time difference of arrival of the samples at the
> receive buffers.
>
> How do we proceed with this ?
>
> Regards
> Siva
>
> Hello Siva,
> recv() will do an aligned reception, i.e. the first samples of both
> streams were received at the same time.
>
> Often, you don't want to *know* *afterwards* the time of reception, you
> want to *define* it beforehand. You can do that by using a stream_cmd
> with a stream_now = false and a timespec to allow you to define when the
> reception is going to take place.
>
> Greetings,
> Marcus
>
> On 04/23/2015 12:28 PM, siva sankar via USRP-users wrote:
>
> Hello List,
>
>
>
> I am using USRP B210 and the UHD version is 003.008.000. We are
> transmitting on one channel and receiving simultaneously on both the
> channels and what we want is the time of arrival of the first sample in
> both the receive buffers.
>
>
>
> We have used the "time_spec_t" to get the time of the first sample but we
> don't know if the time that we are getting is for both the channels or for
> one of the receiver buffers.
>
>
>
> We have tried using two "recv" commands one for each buffer hoping we
> could calculate the time from each metadata parameter passed to the "recv"
> command in one thread but it throws "multi channel alignment" error and
> stops running.
>
>
>
> We also tried to create individual threads for both the rx channels and
> pass different metadata parameters and hence know the time of first sample
> for each buffer. However, this throws segmentation fault.
>
>
>
> Any help on how to calculate the time of first sample for each receive
> buffer will be appreciated.
>
>
>
> Thanks
>
> Siva.
>
>
>
> _______________________________________________
>
> USRP-users mailing list
>
> USRP-users@lists.ettus.com
>
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>
>
>
>
> _______________________________________________
> USRP-users mailing list
> USRP-users@lists.ettus.com
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>
--
Thanks and regards
Siva Sankar.
MM
Marcus Müller
Fri, Apr 24, 2015 6:58 AM
Hi Siva,
ok, so you actually have one B210; that makes things easier, because
that is inherently in sync with itself :)
So what you'd have to do is (not tested, not complete):
stream_cmd_t start_cmd(STREAM_MODE_START_CONTINUOUS);
start_cmd.stream_now = false;
start_cmd.timespec = my_usrp->get_time_now() + time_spec_t(0.5); //start
in 0.5 seconds
stream_args_t str_args;
str_args.channels = boost::assign::list_of(0)(1);
rx_streamer::sptr rx = my_usrp->get_rx_streamer(str_args);
tx_streamer::sptr rx = my_usrp->get_tx_streamer(str_args);
rx->issue_stream_cmd(start_cmd);
tx->issue_stream_cmd(start_cmd);
//spawn two threads, or intermittently rx->recv() and tx->send()
//the first call to recv() and/or send() will possibly block until their
time has come.
Now you'll /know a priori/ that the timestamp of the first received
samples is what is in start_cmd.timespec. Since there is analog and DSP
delay in the B210, you will have to calibrate once for each sampling
rate / analog bandwidth / frequency combination you want to use.
Two things to notice:
- you need a two-channel TX, because the AD9361 wants it that way; you
can't have 2xRX 1xTX, it needs to be 2xRX 2xTX or 1xRX 1xTX. Just set
zero gain for the channel you're not using, and send 0s.
- both RX are running of the same LO, but a different oscillator than
TX; so you'll have to calibrate phase after every tune, because you
can't know which phase the TX LO has relative to the RX LO after a tune.
A clever way of doing this might be connecting an antenna at the
"unused" port, placing it in the middle between your two RX antennas,
and transmitting a short known sequence on it, detecting it with your RX
and estimating the phase offset between RX and TX with that -- you'd
also have a way of knowing the pure loopback delay in your current
configuration like this.
Best regards,
Marcus
On 04/24/2015 07:45 AM, siva sankar wrote:
Hey Marcus,
I am attaching the picture of the set up. The two receivers(Receiver 1
and Receiver 2) shown in the picture are on one USRP B210. We are
trying to calculate the angle of arrival using the TDOA.
These are the equations being used:
Sin θ= S/L;
S = (TDOA)*Speed of light(C);
θ=arcsin(((TDOA)*C)/L);
On Thu, Apr 23, 2015 at 7:38 PM, LOUF Laurent
<laurent.louf@thalesgroup.com mailto:laurent.louf@thalesgroup.com>
wrote:
Hi,
If you just want the time difference, you may want to compute the
correlation between the two signals for different offsets (unit :
samples) and find the offset that gives you the maximum of
correlation (and then translate the number of samples into a time
difference with the sampling frequency). If receivers are not too
far away one from the other, I guess that could be a solution (to
be investigated).
Regards,
Laurent.
*De :*USRP-users [mailto:usrp-users-bounces@lists.ettus.com
<mailto:usrp-users-bounces@lists.ettus.com>] *De la part de* siva
sankar via USRP-users
*Envoyé :* jeudi 23 avril 2015 14:54
*À :* Marcus Müller
*Cc :* usrp-users@lists.ettus.com <mailto:usrp-users@lists.ettus.com>
*Objet :* Re: [USRP-users] Time of arrival of first sample in a 2
Rx setup
Hey Marcus,
Thanks for the reply.
The receivers here are at different distances from the transmitter
and we are looking for the time difference of arrival of the
samples at the receive buffers.
How do we proceed with this ?
Regards
Siva
Hello Siva,
recv() will do an aligned reception, i.e. the first samples of
both streams were received at the same time.
Often, you don't want to /know/ /afterwards/ the time of
reception, you want to /define/ it beforehand. You can do that by
using a stream_cmd with a stream_now = false and a timespec to
allow you to define when the reception is going to take place.
Greetings,
Marcus
On 04/23/2015 12:28 PM, siva sankar via USRP-users wrote:
Hello List,
I am using USRP B210 and the UHD version is 003.008.000. We
are transmitting on one channel and receiving simultaneously
on both the channels and what we want is the time of arrival
of the first sample in both the receive buffers.
We have used the "time_spec_t" to get the time of the first
sample but we don't know if the time that we are getting is
for both the channels or for one of the receiver buffers.
We have tried using two "recv" commands one for each buffer
hoping we could calculate the time from each metadata
parameter passed to the "recv" command in one thread but it
throws "multi channel alignment" error and stops running.
We also tried to create individual threads for both the rx
channels and pass different metadata parameters and hence know
the time of first sample for each buffer. However, this throws
segmentation fault.
Any help on how to calculate the time of first sample for each
receive buffer will be appreciated.
Thanks
Siva.
_______________________________________________
USRP-users mailing list
USRP-users@lists.ettus.com <mailto:USRP-users@lists.ettus.com>
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
_______________________________________________
USRP-users mailing list
USRP-users@lists.ettus.com <mailto:USRP-users@lists.ettus.com>
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
--
Thanks and regards
Siva Sankar.
Hi Siva,
ok, so you actually have one B210; that makes things easier, because
that is inherently in sync with itself :)
So what you'd have to do is (not tested, not complete):
stream_cmd_t start_cmd(STREAM_MODE_START_CONTINUOUS);
start_cmd.stream_now = false;
start_cmd.timespec = my_usrp->get_time_now() + time_spec_t(0.5); //start
in 0.5 seconds
stream_args_t str_args;
str_args.channels = boost::assign::list_of(0)(1);
rx_streamer::sptr rx = my_usrp->get_rx_streamer(str_args);
tx_streamer::sptr rx = my_usrp->get_tx_streamer(str_args);
rx->issue_stream_cmd(start_cmd);
tx->issue_stream_cmd(start_cmd);
//spawn two threads, or intermittently rx->recv() and tx->send()
//the first call to recv() and/or send() will possibly block until their
time has come.
Now you'll /know a priori/ that the timestamp of the first received
samples is what is in start_cmd.timespec. Since there is analog and DSP
delay in the B210, you will have to calibrate once for each sampling
rate / analog bandwidth / frequency combination you want to use.
Two things to notice:
1. you need a two-channel TX, because the AD9361 wants it that way; you
can't have 2xRX 1xTX, it needs to be 2xRX 2xTX or 1xRX 1xTX. Just set
zero gain for the channel you're not using, and send 0s.
2. both RX are running of the same LO, but a different oscillator than
TX; so you'll have to calibrate phase after every tune, because you
can't know which phase the TX LO has relative to the RX LO after a tune.
A clever way of doing this might be connecting an antenna at the
"unused" port, placing it in the middle between your two RX antennas,
and transmitting a short known sequence on it, detecting it with your RX
and estimating the phase offset between RX and TX with that -- you'd
also have a way of knowing the pure loopback delay in your current
configuration like this.
Best regards,
Marcus
On 04/24/2015 07:45 AM, siva sankar wrote:
> Hey Marcus,
>
> I am attaching the picture of the set up. The two receivers(Receiver 1
> and Receiver 2) shown in the picture are on one USRP B210. We are
> trying to calculate the angle of arrival using the TDOA.
> These are the equations being used:
> Sin θ= S/L;
> S = (TDOA)*Speed of light(C);
> θ=arcsin(((TDOA)*C)/L);
>
>
> On Thu, Apr 23, 2015 at 7:38 PM, LOUF Laurent
> <laurent.louf@thalesgroup.com <mailto:laurent.louf@thalesgroup.com>>
> wrote:
>
> Hi,
>
>
>
> If you just want the time difference, you may want to compute the
> correlation between the two signals for different offsets (unit :
> samples) and find the offset that gives you the maximum of
> correlation (and then translate the number of samples into a time
> difference with the sampling frequency). If receivers are not too
> far away one from the other, I guess that could be a solution (to
> be investigated).
>
>
>
> Regards,
>
> Laurent.
>
>
>
>
>
> *De :*USRP-users [mailto:usrp-users-bounces@lists.ettus.com
> <mailto:usrp-users-bounces@lists.ettus.com>] *De la part de* siva
> sankar via USRP-users
> *Envoyé :* jeudi 23 avril 2015 14:54
> *À :* Marcus Müller
> *Cc :* usrp-users@lists.ettus.com <mailto:usrp-users@lists.ettus.com>
> *Objet :* Re: [USRP-users] Time of arrival of first sample in a 2
> Rx setup
>
>
>
> Hey Marcus,
>
> Thanks for the reply.
> The receivers here are at different distances from the transmitter
> and we are looking for the time difference of arrival of the
> samples at the receive buffers.
>
> How do we proceed with this ?
>
> Regards
> Siva
>
> Hello Siva,
> recv() will do an aligned reception, i.e. the first samples of
> both streams were received at the same time.
>
> Often, you don't want to /know/ /afterwards/ the time of
> reception, you want to /define/ it beforehand. You can do that by
> using a stream_cmd with a stream_now = false and a timespec to
> allow you to define when the reception is going to take place.
>
> Greetings,
> Marcus
>
> On 04/23/2015 12:28 PM, siva sankar via USRP-users wrote:
>
> Hello List,
>
>
>
> I am using USRP B210 and the UHD version is 003.008.000. We
> are transmitting on one channel and receiving simultaneously
> on both the channels and what we want is the time of arrival
> of the first sample in both the receive buffers.
>
>
>
> We have used the "time_spec_t" to get the time of the first
> sample but we don't know if the time that we are getting is
> for both the channels or for one of the receiver buffers.
>
>
>
> We have tried using two "recv" commands one for each buffer
> hoping we could calculate the time from each metadata
> parameter passed to the "recv" command in one thread but it
> throws "multi channel alignment" error and stops running.
>
>
>
> We also tried to create individual threads for both the rx
> channels and pass different metadata parameters and hence know
> the time of first sample for each buffer. However, this throws
> segmentation fault.
>
>
>
> Any help on how to calculate the time of first sample for each
> receive buffer will be appreciated.
>
>
>
> Thanks
>
> Siva.
>
>
>
> _______________________________________________
>
> USRP-users mailing list
>
> USRP-users@lists.ettus.com <mailto:USRP-users@lists.ettus.com>
>
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>
>
>
>
> _______________________________________________
> USRP-users mailing list
> USRP-users@lists.ettus.com <mailto:USRP-users@lists.ettus.com>
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>
>
>
>
> --
> Thanks and regards
> Siva Sankar.
RK
Rob Kossler
Wed, Apr 29, 2015 7:57 PM
Siva, Marcus,
I have two comments:
- In addition to the code below, you will need to call
"set_time_unknown_pps" or similar to make sure the timing is the same for
both channels.
- The B210 seems to have an issue with obtaining consistent timing between
TX and RX (
http://lists.ettus.com/pipermail/usrp-users_lists.ettus.com/2015-April/013541.html).
There shouldn't be any issue, however, with the Rx channel to channel
timing so this should work fine for DOA.
Rob
On Fri, Apr 24, 2015 at 2:58 AM, Marcus Müller usrp-users@lists.ettus.com
wrote:
Hi Siva,
ok, so you actually have one B210; that makes things easier, because that
is inherently in sync with itself :)
So what you'd have to do is (not tested, not complete):
stream_cmd_t start_cmd(STREAM_MODE_START_CONTINUOUS);
start_cmd.stream_now = false;
start_cmd.timespec = my_usrp->get_time_now() + time_spec_t(0.5); //start
in 0.5 seconds
stream_args_t str_args;
str_args.channels = boost::assign::list_of(0)(1);
rx_streamer::sptr rx = my_usrp->get_rx_streamer(str_args);
tx_streamer::sptr rx = my_usrp->get_tx_streamer(str_args);
rx->issue_stream_cmd(start_cmd);
tx->issue_stream_cmd(start_cmd);
//spawn two threads, or intermittently rx->recv() and tx->send()
//the first call to recv() and/or send() will possibly block until their
time has come.
Now you'll know a priori that the timestamp of the first received
samples is what is in start_cmd.timespec. Since there is analog and DSP
delay in the B210, you will have to calibrate once for each sampling rate /
analog bandwidth / frequency combination you want to use.
Two things to notice:
- you need a two-channel TX, because the AD9361 wants it that way; you
can't have 2xRX 1xTX, it needs to be 2xRX 2xTX or 1xRX 1xTX. Just set zero
gain for the channel you're not using, and send 0s.
- both RX are running of the same LO, but a different oscillator than TX;
so you'll have to calibrate phase after every tune, because you can't know
which phase the TX LO has relative to the RX LO after a tune. A clever way
of doing this might be connecting an antenna at the "unused" port, placing
it in the middle between your two RX antennas, and transmitting a short
known sequence on it, detecting it with your RX and estimating the phase
offset between RX and TX with that -- you'd also have a way of knowing the
pure loopback delay in your current configuration like this.
Best regards,
Marcus
On 04/24/2015 07:45 AM, siva sankar wrote:
Hey Marcus,
I am attaching the picture of the set up. The two receivers(Receiver 1
and Receiver 2) shown in the picture are on one USRP B210. We are trying
to calculate the angle of arrival using the TDOA.
These are the equations being used:
Sin θ= S/L;
S = (TDOA)*Speed of light(C);
θ=arcsin(((TDOA)*C)/L);
On Thu, Apr 23, 2015 at 7:38 PM, LOUF Laurent <
laurent.louf@thalesgroup.com> wrote:
Hi,
If you just want the time difference, you may want to compute the
correlation between the two signals for different offsets (unit : samples)
and find the offset that gives you the maximum of correlation (and then
translate the number of samples into a time difference with the sampling
frequency). If receivers are not too far away one from the other, I guess
that could be a solution (to be investigated).
Regards,
Laurent.
De : USRP-users [mailto:usrp-users-bounces@lists.ettus.com] De la
part de siva sankar via USRP-users
Envoyé : jeudi 23 avril 2015 14:54
À : Marcus Müller
Cc : usrp-users@lists.ettus.com
Objet : Re: [USRP-users] Time of arrival of first sample in a 2 Rx
setup
Hey Marcus,
Thanks for the reply.
The receivers here are at different distances from the transmitter and we
are looking for the time difference of arrival of the samples at the
receive buffers.
How do we proceed with this ?
Regards
Siva
Hello Siva,
recv() will do an aligned reception, i.e. the first samples of both
streams were received at the same time.
Often, you don't want to know afterwards the time of reception, you
want to define it beforehand. You can do that by using a stream_cmd
with a stream_now = false and a timespec to allow you to define when the
reception is going to take place.
Greetings,
Marcus
On 04/23/2015 12:28 PM, siva sankar via USRP-users wrote:
Hello List,
I am using USRP B210 and the UHD version is 003.008.000. We are
transmitting on one channel and receiving simultaneously on both the
channels and what we want is the time of arrival of the first sample in
both the receive buffers.
We have used the "time_spec_t" to get the time of the first sample but we
don't know if the time that we are getting is for both the channels or for
one of the receiver buffers.
We have tried using two "recv" commands one for each buffer hoping we
could calculate the time from each metadata parameter passed to the "recv"
command in one thread but it throws "multi channel alignment" error and
stops running.
We also tried to create individual threads for both the rx channels and
pass different metadata parameters and hence know the time of first sample
for each buffer. However, this throws segmentation fault.
Any help on how to calculate the time of first sample for each receive
buffer will be appreciated.
Thanks
Siva.
USRP-users mailing list
USRP-users@lists.ettus.com
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
USRP-users mailing list
USRP-users@lists.ettus.com
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
Siva, Marcus,
I have two comments:
1) In addition to the code below, you will need to call
"set_time_unknown_pps" or similar to make sure the timing is the same for
both channels.
2) The B210 seems to have an issue with obtaining consistent timing between
TX and RX (
http://lists.ettus.com/pipermail/usrp-users_lists.ettus.com/2015-April/013541.html).
There shouldn't be any issue, however, with the Rx channel to channel
timing so this should work fine for DOA.
Rob
On Fri, Apr 24, 2015 at 2:58 AM, Marcus Müller <usrp-users@lists.ettus.com>
wrote:
> Hi Siva,
>
> ok, so you actually have one B210; that makes things easier, because that
> is inherently in sync with itself :)
> So what you'd have to do is (not tested, not complete):
>
> stream_cmd_t start_cmd(STREAM_MODE_START_CONTINUOUS);
> start_cmd.stream_now = false;
> start_cmd.timespec = my_usrp->get_time_now() + time_spec_t(0.5); //start
> in 0.5 seconds
>
> stream_args_t str_args;
> str_args.channels = boost::assign::list_of(0)(1);
>
> rx_streamer::sptr rx = my_usrp->get_rx_streamer(str_args);
> tx_streamer::sptr rx = my_usrp->get_tx_streamer(str_args);
>
> rx->issue_stream_cmd(start_cmd);
> tx->issue_stream_cmd(start_cmd);
> //spawn two threads, or intermittently rx->recv() and tx->send()
> //the first call to recv() and/or send() will possibly block until their
> time has come.
>
> Now you'll *know a priori* that the timestamp of the first received
> samples is what is in start_cmd.timespec. Since there is analog and DSP
> delay in the B210, you will have to calibrate once for each sampling rate /
> analog bandwidth / frequency combination you want to use.
>
> Two things to notice:
> 1. you need a two-channel TX, because the AD9361 wants it that way; you
> can't have 2xRX 1xTX, it needs to be 2xRX 2xTX or 1xRX 1xTX. Just set zero
> gain for the channel you're not using, and send 0s.
> 2. both RX are running of the same LO, but a different oscillator than TX;
> so you'll have to calibrate phase after every tune, because you can't know
> which phase the TX LO has relative to the RX LO after a tune. A clever way
> of doing this might be connecting an antenna at the "unused" port, placing
> it in the middle between your two RX antennas, and transmitting a short
> known sequence on it, detecting it with your RX and estimating the phase
> offset between RX and TX with that -- you'd also have a way of knowing the
> pure loopback delay in your current configuration like this.
>
> Best regards,
> Marcus
>
>
> On 04/24/2015 07:45 AM, siva sankar wrote:
>
> Hey Marcus,
>
> I am attaching the picture of the set up. The two receivers(Receiver 1
> and Receiver 2) shown in the picture are on one USRP B210. We are trying
> to calculate the angle of arrival using the TDOA.
> These are the equations being used:
> Sin θ= S/L;
> S = (TDOA)*Speed of light(C);
> θ=arcsin(((TDOA)*C)/L);
>
>
> On Thu, Apr 23, 2015 at 7:38 PM, LOUF Laurent <
> laurent.louf@thalesgroup.com> wrote:
>
>> Hi,
>>
>>
>>
>> If you just want the time difference, you may want to compute the
>> correlation between the two signals for different offsets (unit : samples)
>> and find the offset that gives you the maximum of correlation (and then
>> translate the number of samples into a time difference with the sampling
>> frequency). If receivers are not too far away one from the other, I guess
>> that could be a solution (to be investigated).
>>
>>
>>
>> Regards,
>>
>> Laurent.
>>
>>
>>
>>
>>
>> *De :* USRP-users [mailto:usrp-users-bounces@lists.ettus.com] *De la
>> part de* siva sankar via USRP-users
>> *Envoyé :* jeudi 23 avril 2015 14:54
>> *À :* Marcus Müller
>> *Cc :* usrp-users@lists.ettus.com
>> *Objet :* Re: [USRP-users] Time of arrival of first sample in a 2 Rx
>> setup
>>
>>
>>
>> Hey Marcus,
>>
>> Thanks for the reply.
>> The receivers here are at different distances from the transmitter and we
>> are looking for the time difference of arrival of the samples at the
>> receive buffers.
>>
>> How do we proceed with this ?
>>
>> Regards
>> Siva
>>
>> Hello Siva,
>> recv() will do an aligned reception, i.e. the first samples of both
>> streams were received at the same time.
>>
>> Often, you don't want to *know* *afterwards* the time of reception, you
>> want to *define* it beforehand. You can do that by using a stream_cmd
>> with a stream_now = false and a timespec to allow you to define when the
>> reception is going to take place.
>>
>> Greetings,
>> Marcus
>>
>> On 04/23/2015 12:28 PM, siva sankar via USRP-users wrote:
>>
>> Hello List,
>>
>>
>>
>> I am using USRP B210 and the UHD version is 003.008.000. We are
>> transmitting on one channel and receiving simultaneously on both the
>> channels and what we want is the time of arrival of the first sample in
>> both the receive buffers.
>>
>>
>>
>> We have used the "time_spec_t" to get the time of the first sample but we
>> don't know if the time that we are getting is for both the channels or for
>> one of the receiver buffers.
>>
>>
>>
>> We have tried using two "recv" commands one for each buffer hoping we
>> could calculate the time from each metadata parameter passed to the "recv"
>> command in one thread but it throws "multi channel alignment" error and
>> stops running.
>>
>>
>>
>> We also tried to create individual threads for both the rx channels and
>> pass different metadata parameters and hence know the time of first sample
>> for each buffer. However, this throws segmentation fault.
>>
>>
>>
>> Any help on how to calculate the time of first sample for each receive
>> buffer will be appreciated.
>>
>>
>>
>> Thanks
>>
>> Siva.
>>
>>
>>
>> _______________________________________________
>>
>> USRP-users mailing list
>>
>> USRP-users@lists.ettus.com
>>
>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>>
>>
>>
>>
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>>
>
>
>
> --
> Thanks and regards
> Siva Sankar.
>
>
>
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> USRP-users@lists.ettus.com
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>
>
