Hi all,
I met a werid problem when receiving. When I ran ‘rx_samples_to_file’
example to receive signal from a signal source, e.g. radio station, on
two
USRPN210s, the amplitude of received signals are different, seen from
gnuplot.
Does anyone know why this happenes? I guess this is the problem of USRP,
because I ran the same program, set the same parameters for
‘rx_samples_to_file’, receive the same signal source and the two USRP
N210s
were placed next to each other on the table.
Is there a way to set USRP/daughterboard so that the received signals
have
the same amplitude on two USRPs or adjust other parameters in
gnuradio/uhd
to do that?
Regards,
Jamie
On Tue, 22 May 2012 22:40:11 +1000, Jamie Wo wrote:
Hi all,
I met a werid problem when receiving. When I ran ‘rx_samples_to_file’
example to receive signal from a signal source, e.g. radio station, on
two USRPN210s, the amplitude of received signals are different, seen
from gnuplot.
Does anyone know why this happenes? I guess this is
the problem of USRP, because I ran the same program, set the same
parameters for ‘rx_samples_to_file’, receive the same signal source and
the two USRP N210s were placed next to each other on the table.
Is
there a way to set USRP/daughterboard so that the received signals have
the same amplitude on two USRPs or adjust other parameters in
gnuradio/uhd to do that?
Regards,
Jamie
Analog electronics
can have variability in gain response, perhaps as much as 2dB for
nominally-identical daughter-cards, and identical gain settings.
Furthermore, propagation can often lead to variations in signal
strength between two identical receivers, with identical antennae even
in the same physical area, especially in the presence of multi-path
signal propagation.
Thanks for your reply.
I understand the received signals on two USRPs are not likely to be
exactly
the same. I wonder is there a way to adjust either USRP or modify
software
setting in gnuradio to make the amplitude close?
Actually, what I got from two USRPN210s has a big difference in
amplitude,
as shown in the attachment. How can I handle this?
Regards,
Jamie
Hi Marcus,
Thanks. The daughter boards I am using are WBXs.
I can understand how to use multiply-const block to change the amplitude
of
the received signal, but what does the first method mean?
Does it mean to set the parameter in help message “- - gain arg
gain
for the RF chain” or on hardware level? I did not see any button on
motherboard or daughterboard for adjusting RF gain.
Regards,
Jamie
You don’t say what daughtercards you’re using --many of them allow
you to set the RF (analog) gain on the card.
YOu can also modify the
magnitudes of the signals using a multiply-const block in Gnu Radio.
-Marcus
On Tue, 22 May 2012 23:23:49 +1000, Jamie Wo wrote:
Thanks for your reply.
I understand the received signals on two
USRPs are not likely to be exactly the same. I wonder is there a way to
adjust either USRP or modify software setting in gnuradio to make the
amplitude close?
Actually, what I got from two USRPN210s has a big
difference in amplitude, as shown in the attachment. How can I handle
this?
Regards,
Jamie
On Tue, May 22, 2012 at 10:56 PM,
wrote:
On Tue, 22 May 2012 22:40:11 +1000, Jamie Wo wrote:
Hi all,
I met a werid problem when receiving. When I ran
‘rx_samples_to_file’ example to receive signal from a signal source,
e.g. radio station, on two USRPN210s, the amplitude of received signals
are different, seen from gnuplot.
Does anyone know why this
happenes? I guess this is the problem of USRP, because I ran the same
program, set the same parameters for ‘rx_samples_to_file’, receive the
same signal source and the two USRP N210s were placed next to each other
on the table.
Is there a way to set USRP/daughterboard so that the
received signals have the same amplitude on two USRPs or adjust other
parameters in gnuradio/uhd to do that?
Regards,
Jamie
Analog electronics can have variability in gain response, perhaps as
much as 2dB for nominally-identical daughter-cards, and identical gain
settings.
Furthermore, propagation can often lead to variations
in signal strength between two identical receivers, with identical
antennae even in the same physical area, especially in the presence of
multi-path signal propagation.
Discuss-gnuradio
mailing list
[email protected] [1]
Discuss-gnuradio Info Page [2]
Links:
Hi Marcus,
Thanks for your reply. However, I already set the gain to 30 on the two
USRPs. I mean the pictures I attached before is based on the same gain
setting. Is there any other method to control this? The big difference
in
amplitude looks really strange. Should be a way to solve this.
Regards,
Jamie
One of the controllable parameters of a USRP source/sink is gain.
If you’re using rx_samples_to_file, then yes the “–gain” argument is
the one you want–this controls the analog RF gain of the board.
-Marcus
On Tue, 22 May 2012 23:42:40 +1000, Jamie Wo wrote:
Hi
Marcus,
Thanks. The daughter boards I am using are WBXs.
I
can understand how to use multiply-const block to change the amplitude
of the received signal, but what does the first method mean?
Does
it mean to set the parameter in help message “- - gain arg gain for the
RF chain” or on hardware level? I did not see any button on motherboard
or daughterboard for adjusting RF gain.
Regards,
Jamie
On
Tue, May 22, 2012 at 11:27 PM, wrote:
You don’t say what
daughtercards you’re using --many of them allow you to set the RF
(analog) gain on the card.
YOu can also modify the magnitudes of
the signals using a multiply-const block in Gnu Radio.
-Marcus
On Tue, 22 May 2012 23:23:49 +1000, Jamie Wo wrote:
Thanks for your reply.
I understand the received signals on
two USRPs are not likely to be exactly the same. I wonder is there a way
to adjust either USRP or modify software setting in gnuradio to make the
amplitude close?
Actually, what I got from two USRPN210s has a
big difference in amplitude, as shown in the attachment. How can I
handle this?
Regards,
Jamie
On Tue, May 22,
2012 at 10:56 PM, wrote:
On Tue, 22 May 2012 22:40:11 +1000,
Jamie Wo wrote:
Hi all,
I met a werid problem when
receiving. When I ran ‘rx_samples_to_file’ example to receive signal
from a signal source, e.g. radio station, on two USRPN210s, the
amplitude of received signals are different, seen from gnuplot.
Does anyone know why this happenes? I guess this is the problem of USRP,
because I ran the same program, set the same parameters for
‘rx_samples_to_file’, receive the same signal source and the two USRP
N210s were placed next to each other on the table.
Is there a way
to set USRP/daughterboard so that the received signals have the same
amplitude on two USRPs or adjust other parameters in gnuradio/uhd to do
that?
Regards,
Jamie
Analog electronics can
have variability in gain response, perhaps as much as 2dB for
nominally-identical daughter-cards, and identical gain settings.
Furthermore, propagation can often lead to variations in signal
strength between two identical receivers, with identical antennae even
in the same physical area, especially in the presence of multi-path
signal propagation.
Discuss-gnuradio
mailing list
[email protected] [1]
Discuss-gnuradio Info Page [2]
Links:
Hi Marcus,
I really appreciate your answers. I will check that.
Regards,
Jamie
There are a couple of possibilities:
-
You aren’t on the correct
antenna port on one of your systems, so your antenna is connected to
something other than the port you’re listening on
-
You have damaged
the LNA on one of your WBX boards, and so it is vastly less sensitive
than the other one
-Marcus
On Tue, 22 May 2012 23:56:45 +1000, Jamie
Wo wrote:
Hi Marcus,
Thanks for your reply. However, I already
set the gain to 30 on the two USRPs. I mean the pictures I attached
before is based on the same gain setting. Is there any other method to
control this? The big difference in amplitude looks really strange.
Should be a way to solve this.