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View all threadsUsable bandwidth of X300 USRP with UBX-160 daughterboard
Hi All,
I have a question about the usable bandwidth of the X300 USRP / UBX-160
daughterboard combo at sampling rates below 200 Msps:
As I understand it, the UBX-160 receiver has an analog (hardware) filter
before the ADC that limits the usable bandwidth to 160 MHz, while the ADC
runs at 200 Msps. Therefore the usable bandwidth is around 80% of the
sample rate.
My question is: What is the usable bandwidth at lower sampling rates?
Does the 80% factor always apply?
For example, if I set the decimation factor to 4, so that my sampling rate
is 50 Msps, does this mean that the usable bandwidth will be 40 MHz?
Thanks & Regards,
Brendan.
There will always be some edge roll off. Decimation includes filtering and those filters cannot be infinitely steep.
Sent from my iPhone
On Feb 18, 2025, at 2:12 AM, Brendan Horsfield brendan.horsfield@vectalabs.com wrote:
Hi All,
I have a question about the usable bandwidth of the X300 USRP / UBX-160 daughterboard combo at sampling rates below 200 Msps:
As I understand it, the UBX-160 receiver has an analog (hardware) filter before the ADC that limits the usable bandwidth to 160 MHz, while the ADC runs at 200 Msps. Therefore the usable bandwidth is around 80% of the sample rate.
My question is: What is the usable bandwidth at lower sampling rates? Does the 80% factor always apply?
For example, if I set the decimation factor to 4, so that my sampling rate is 50 Msps, does this mean that the usable bandwidth will be 40 MHz?
Thanks & Regards,
Brendan.
USRP-users mailing list -- usrp-users@lists.ettus.com
To unsubscribe send an email to usrp-users-leave@lists.ettus.com
Yes, I assumed that was the case. However, it is not clear from the X300
documentation how sharp those filters are. Can you tell me how wide the
transition band is at the lower sample rates?
To give you some context, I would like to use an X300 (or X310) with a
UBX-160 daughterboard to digitise the entire 2.4 GHz Wi-Fi band, which is
83.5 MHz wide. Ideally I would like to use a sample rate of 100 Msps to
minimise the data rate between the USRP and the host PC. However, before I
do this I need to be certain that the usable bandwidth at this sample rate
will be greater than 83.5 MHz. Is this information documented somewhere?
On Tue, 18 Feb 2025 at 23:11, Marcus D Leech patchvonbraun@gmail.com
wrote:
There will always be some edge roll off. Decimation includes filtering and
those filters cannot be infinitely steep.
Sent from my iPhone
On Feb 18, 2025, at 2:12 AM, Brendan Horsfield <
brendan.horsfield@vectalabs.com> wrote:
Hi All,
I have a question about the usable bandwidth of the X300 USRP / UBX-160
daughterboard combo at sampling rates below 200 Msps:
As I understand it, the UBX-160 receiver has an analog (hardware) filter
before the ADC that limits the usable bandwidth to 160 MHz, while the ADC
runs at 200 Msps. Therefore the usable bandwidth is around 80% of the
sample rate.
My question is: What is the usable bandwidth at lower sampling rates?
Does the 80% factor always apply?
For example, if I set the decimation factor to 4, so that my sampling
rate is 50 Msps, does this mean that the usable bandwidth will be 40 MHz?
Thanks & Regards,
Brendan.
USRP-users mailing list -- usrp-users@lists.ettus.com
To unsubscribe send an email to usrp-users-leave@lists.ettus.com
On 18/02/2025 18:45, Brendan Horsfield wrote:
Yes, I assumed that was the case. However, it is not clear from the
X300 documentation how sharp those filters are. Can you tell me how
wide the transition band is at the lower sample rates?
To give you some context, I would like to use an X300 (or X310) with a
UBX-160 daughterboard to digitise the entire 2.4 GHz Wi-Fi band, which
is 83.5 MHz wide. Ideally I would like to use a sample rate of 100
Msps to minimise the data rate between the USRP and the host PC.
However, before I do this I need to be certain that the usable
bandwidth at this sample rate will be greater than 83.5 MHz. Is this
information documented somewhere?
It somewhat depends on the decimation. If the decimation has a factor
of two or 4, the edge roll-off is fairly sharp. Otherwise,
there's a half-band filter in-place that causes a less-desirable
pass-band.
But I don't know, precisely, what the transition band is in the "nicer"
filter shapes.
If you have an X310+UBX-160, you can always just use a noise source, and
measure it yourself to see if it's appropriate for
your application.
On Tue, 18 Feb 2025 at 23:11, Marcus D Leech patchvonbraun@gmail.com
wrote:
There will always be some edge roll off. Decimation includes
filtering and those filters cannot be infinitely steep.
Sent from my iPhone
On Feb 18, 2025, at 2:12 AM, Brendan Horsfield
<brendan.horsfield@vectalabs.com> wrote:
Hi All,
I have a question about the usable bandwidth of the X300 USRP /
UBX-160 daughterboard combo at sampling rates below 200 Msps:
As I understand it, the UBX-160 receiver has an analog
(hardware) filter before the ADC that limits the usable bandwidth
to 160 MHz, while the ADC runs at 200 Msps. Therefore the usable
bandwidth is around 80% of the sample rate.
My question is: What is the usable bandwidth at lower sampling
rates? Does the 80% factor always apply?
For example, if I set the decimation factor to 4, so that my
sampling rate is 50 Msps, does this mean that the usable bandwidth
will be 40 MHz?
Thanks & Regards,
Brendan.
USRP-users mailing list -- usrp-users@lists.ettus.com
To unsubscribe send an email to usrp-users-leave@lists.ettus.com
Thanks for the suggestion about the noise source -- that's what I would
normally do. Unfortunately I haven't actually purchased the hardware yet
-- I was hoping to clarify this issue before raising a purchase order.
Perhaps I should follow this up with one of the application engineers at
NI? They might have access to an X310+UBX-160 system that they can use to
answer my question directly.
Thanks again for your help in this matter.
Regards,
Brendan.
On Wed, 19 Feb 2025 at 09:55, Marcus D. Leech patchvonbraun@gmail.com
wrote:
On 18/02/2025 18:45, Brendan Horsfield wrote:
Yes, I assumed that was the case. However, it is not clear from the X300
documentation how sharp those filters are. Can you tell me how wide the
transition band is at the lower sample rates?
To give you some context, I would like to use an X300 (or X310) with a
UBX-160 daughterboard to digitise the entire 2.4 GHz Wi-Fi band, which is
83.5 MHz wide. Ideally I would like to use a sample rate of 100 Msps to
minimise the data rate between the USRP and the host PC. However, before I
do this I need to be certain that the usable bandwidth at this sample rate
will be greater than 83.5 MHz. Is this information documented somewhere?
It somewhat depends on the decimation. If the decimation has a factor of
two or 4, the edge roll-off is fairly sharp. Otherwise,
there's a half-band filter in-place that causes a less-desirable
pass-band.
But I don't know, precisely, what the transition band is in the "nicer"
filter shapes.
If you have an X310+UBX-160, you can always just use a noise source, and
measure it yourself to see if it's appropriate for
your application.
On Tue, 18 Feb 2025 at 23:11, Marcus D Leech patchvonbraun@gmail.com
wrote:
There will always be some edge roll off. Decimation includes filtering
and those filters cannot be infinitely steep.
Sent from my iPhone
On Feb 18, 2025, at 2:12 AM, Brendan Horsfield <
brendan.horsfield@vectalabs.com> wrote:
Hi All,
I have a question about the usable bandwidth of the X300 USRP / UBX-160
daughterboard combo at sampling rates below 200 Msps:
As I understand it, the UBX-160 receiver has an analog (hardware)
filter before the ADC that limits the usable bandwidth to 160 MHz, while
the ADC runs at 200 Msps. Therefore the usable bandwidth is around 80% of
the sample rate.
My question is: What is the usable bandwidth at lower sampling rates?
Does the 80% factor always apply?
For example, if I set the decimation factor to 4, so that my sampling
rate is 50 Msps, does this mean that the usable bandwidth will be 40 MHz?
Thanks & Regards,
Brendan.
USRP-users mailing list -- usrp-users@lists.ettus.com
To unsubscribe send an email to usrp-users-leave@lists.ettus.com
Just test it yourself. Send a wideband noise signal into the X300 and
see what it looks like with a graphical receiver like gqrx. Here's an
example. It's a B210 sending a 10 MHz wide noise signal being received
by a bladeRF with the baseband bandwidth set to 6 MHz. You can see the
actual bandwidth (a little greater than 6 MHz) and the slope of the
roll-off.
I've attached the 10 MHz noise generator GNU Radio flow graph. You'll
need to modify it for your specifics.
Ron
bladeRF bandwidth
On 2/18/25 15:45, Brendan Horsfield wrote:
Yes, I assumed that was the case. However, it is not clear from the
X300 documentation how sharp those filters are. Can you tell me how
wide the transition band is at the lower sample rates?
To give you some context, I would like to use an X300 (or X310) with a
UBX-160 daughterboard to digitise the entire 2.4 GHz Wi-Fi band, which
is 83.5 MHz wide. Ideally I would like to use a sample rate of 100
Msps to minimise the data rate between the USRP and the host PC.
However, before I do this I need to be certain that the usable
bandwidth at this sample rate will be greater than 83.5 MHz. Is this
information documented somewhere?
On Tue, 18 Feb 2025 at 23:11, Marcus D Leech patchvonbraun@gmail.com
wrote:
There will always be some edge roll off. Decimation includes
filtering and those filters cannot be infinitely steep.
Sent from my iPhone
On Feb 18, 2025, at 2:12 AM, Brendan Horsfield
<brendan.horsfield@vectalabs.com> wrote:
Hi All,
I have a question about the usable bandwidth of the X300 USRP /
UBX-160 daughterboard combo at sampling rates below 200 Msps:
As I understand it, the UBX-160 receiver has an analog
(hardware) filter before the ADC that limits the usable bandwidth
to 160 MHz, while the ADC runs at 200 Msps. Therefore the usable
bandwidth is around 80% of the sample rate.
My question is: What is the usable bandwidth at lower sampling
rates? Does the 80% factor always apply?
For example, if I set the decimation factor to 4, so that my
sampling rate is 50 Msps, does this mean that the usable bandwidth
will be 40 MHz?
Thanks & Regards,
Brendan.
USRP-users mailing list -- usrp-users@lists.ettus.com
To unsubscribe send an email to usrp-users-leave@lists.ettus.com
USRP-users mailing list --usrp-users@lists.ettus.com
To unsubscribe send an email tousrp-users-leave@lists.ettus.com
On 18/02/2025 19:13, Brendan Horsfield wrote:
Thanks for the suggestion about the noise source -- that's what I
would normally do. Unfortunately I haven't actually purchased the
hardware yet -- I was hoping to clarify this issue before raising a
purchase order.
Perhaps I should follow this up with one of the application engineers
at NI? They might have access to an X310+UBX-160 system that they can
use to answer my question directly.
Thanks again for your help in this matter.
Regards,
Brendan.
I actually do work for NI on USRP devices (on a very very very part-time
basis). My X310 is currently elsewhere, and not populated
with a UBX-160.
On Wed, 19 Feb 2025 at 09:55, Marcus D. Leech
patchvonbraun@gmail.com wrote:
On 18/02/2025 18:45, Brendan Horsfield wrote:
Yes, I assumed that was the case. However, it is not clear from
the X300 documentation how sharp those filters are. Can you tell
me how wide the transition band is at the lower sample rates?
To give you some context, I would like to use an X300 (or X310)
with a UBX-160 daughterboard to digitise the entire 2.4 GHz Wi-Fi
band, which is 83.5 MHz wide. Ideally I would like to use a
sample rate of 100 Msps to minimise the data rate between the
USRP and the host PC. However, before I do this I need to be
certain that the usable bandwidth at this sample rate will be
greater than 83.5 MHz. Is this information documented somewhere?
It somewhat depends on the decimation. If the decimation has a
factor of two or 4, the edge roll-off is fairly sharp. Otherwise,
there's a half-band filter in-place that causes a less-desirable
pass-band.
But I don't know, precisely, what the transition band is in the
"nicer" filter shapes.
If you have an X310+UBX-160, you can always just use a noise
source, and measure it yourself to see if it's appropriate for
your application.
On Tue, 18 Feb 2025 at 23:11, Marcus D Leech
<patchvonbraun@gmail.com> wrote:
There will always be some edge roll off. Decimation includes
filtering and those filters cannot be infinitely steep.
Sent from my iPhone
On Feb 18, 2025, at 2:12 AM, Brendan Horsfield
<brendan.horsfield@vectalabs.com> wrote:
Hi All,
I have a question about the usable bandwidth of the X300
USRP / UBX-160 daughterboard combo at sampling rates below
200 Msps:
As I understand it, the UBX-160 receiver has an analog
(hardware) filter before the ADC that limits the usable
bandwidth to 160 MHz, while the ADC runs at 200 Msps.
Therefore the usable bandwidth is around 80% of the sample rate.
My question is: What is the usable bandwidth at lower
sampling rates? Does the 80% factor always apply?
For example, if I set the decimation factor to 4, so that
my sampling rate is 50 Msps, does this mean that the usable
bandwidth will be 40 MHz?
Thanks & Regards,
Brendan.
USRP-users mailing list -- usrp-users@lists.ettus.com
To unsubscribe send an email to
usrp-users-leave@lists.ettus.com
On 18/02/2025 19:14, Ron Economos via USRP-users wrote:
Just test it yourself. Send a wideband noise signal into the X300 and
see what it looks like with a graphical receiver like gqrx. Here's an
example. It's a B210 sending a 10 MHz wide noise signal being received
by a bladeRF with the baseband bandwidth set to 6 MHz. You can see the
actual bandwidth (a little greater than 6 MHz) and the slope of the
roll-off.
I've attached the 10 MHz noise generator GNU Radio flow graph. You'll
need to modify it for your specifics.
Ron
Unfortunately, the DDC implementation on B210 is different than on X310,
so not quite comparable....
bladeRF bandwidth
On 2/18/25 15:45, Brendan Horsfield wrote:
Yes, I assumed that was the case. However, it is not clear from the
X300 documentation how sharp those filters are. Can you tell me how
wide the transition band is at the lower sample rates?
To give you some context, I would like to use an X300 (or X310) with
a UBX-160 daughterboard to digitise the entire 2.4 GHz Wi-Fi band,
which is 83.5 MHz wide. Ideally I would like to use a sample rate of
100 Msps to minimise the data rate between the USRP and the host PC.
However, before I do this I need to be certain that the usable
bandwidth at this sample rate will be greater than 83.5 MHz. Is this
information documented somewhere?
On Tue, 18 Feb 2025 at 23:11, Marcus D Leech
patchvonbraun@gmail.com wrote:
There will always be some edge roll off. Decimation includes
filtering and those filters cannot be infinitely steep.
Sent from my iPhone
On Feb 18, 2025, at 2:12 AM, Brendan Horsfield
<brendan.horsfield@vectalabs.com> wrote:
Hi All,
I have a question about the usable bandwidth of the X300 USRP /
UBX-160 daughterboard combo at sampling rates below 200 Msps:
As I understand it, the UBX-160 receiver has an analog
(hardware) filter before the ADC that limits the usable bandwidth
to 160 MHz, while the ADC runs at 200 Msps. Therefore the usable
bandwidth is around 80% of the sample rate.
My question is: What is the usable bandwidth at lower sampling
rates? Does the 80% factor always apply?
For example, if I set the decimation factor to 4, so that my
sampling rate is 50 Msps, does this mean that the usable
bandwidth will be 40 MHz?
Thanks & Regards,
Brendan.
USRP-users mailing list -- usrp-users@lists.ettus.com
To unsubscribe send an email to usrp-users-leave@lists.ettus.com
USRP-users mailing list --usrp-users@lists.ettus.com
To unsubscribe send an email tousrp-users-leave@lists.ettus.com
USRP-users mailing list --usrp-users@lists.ettus.com
To unsubscribe send an email tousrp-users-leave@lists.ettus.com
I thought your name sounded familiar! 🙂
Overall the X310+UBX-160 appears to be a good fit to our requirements. My
original question was really about ensuring that our host PC & network
interface have sufficient bandwidth to ingest the IQ data from a pair of
UBX-160s. It would be nice (although not essential) if we could run one
channel at 100 Msps, and the other at 200 Msps, to reduce the bandwidth
requirements on the backend hardware.
On Wed, 19 Feb 2025 at 10:17, Marcus D. Leech patchvonbraun@gmail.com
wrote:
On 18/02/2025 19:13, Brendan Horsfield wrote:
Thanks for the suggestion about the noise source -- that's what I would
normally do. Unfortunately I haven't actually purchased the hardware yet
-- I was hoping to clarify this issue before raising a purchase order.
Perhaps I should follow this up with one of the application engineers at
NI? They might have access to an X310+UBX-160 system that they can use to
answer my question directly.
Thanks again for your help in this matter.
Regards,
Brendan.
I actually do work for NI on USRP devices (on a very very very part-time
basis). My X310 is currently elsewhere, and not populated
with a UBX-160.
On Wed, 19 Feb 2025 at 09:55, Marcus D. Leech patchvonbraun@gmail.com
wrote:
On 18/02/2025 18:45, Brendan Horsfield wrote:
Yes, I assumed that was the case. However, it is not clear from the X300
documentation how sharp those filters are. Can you tell me how wide the
transition band is at the lower sample rates?
To give you some context, I would like to use an X300 (or X310) with a
UBX-160 daughterboard to digitise the entire 2.4 GHz Wi-Fi band, which is
83.5 MHz wide. Ideally I would like to use a sample rate of 100 Msps to
minimise the data rate between the USRP and the host PC. However, before I
do this I need to be certain that the usable bandwidth at this sample rate
will be greater than 83.5 MHz. Is this information documented somewhere?
It somewhat depends on the decimation. If the decimation has a factor of
two or 4, the edge roll-off is fairly sharp. Otherwise,
there's a half-band filter in-place that causes a less-desirable
pass-band.
But I don't know, precisely, what the transition band is in the "nicer"
filter shapes.
If you have an X310+UBX-160, you can always just use a noise source, and
measure it yourself to see if it's appropriate for
your application.
On Tue, 18 Feb 2025 at 23:11, Marcus D Leech patchvonbraun@gmail.com
wrote:
There will always be some edge roll off. Decimation includes filtering
and those filters cannot be infinitely steep.
Sent from my iPhone
On Feb 18, 2025, at 2:12 AM, Brendan Horsfield <
brendan.horsfield@vectalabs.com> wrote:
Hi All,
I have a question about the usable bandwidth of the X300 USRP /
UBX-160 daughterboard combo at sampling rates below 200 Msps:
As I understand it, the UBX-160 receiver has an analog (hardware)
filter before the ADC that limits the usable bandwidth to 160 MHz, while
the ADC runs at 200 Msps. Therefore the usable bandwidth is around 80% of
the sample rate.
My question is: What is the usable bandwidth at lower sampling
rates? Does the 80% factor always apply?
For example, if I set the decimation factor to 4, so that my sampling
rate is 50 Msps, does this mean that the usable bandwidth will be 40 MHz?
Thanks & Regards,
Brendan.
USRP-users mailing list -- usrp-users@lists.ettus.com
To unsubscribe send an email to usrp-users-leave@lists.ettus.com
On 18/02/2025 19:26, Brendan Horsfield wrote:
I thought your name sounded familiar! 🙂
Overall the X310+UBX-160 appears to be a good fit to our
requirements. My original question was really about ensuring that our
host PC & network interface have sufficient bandwidth to ingest the IQ
data from a pair of UBX-160s. It would be nice (although not
essential) if we could run one channel at 100 Msps, and the other at
200 Msps, to reduce the bandwidth requirements on the backend hardware.
You'd need to have separate streamers to support two different sample
rates, and two 10Gbe interfaces.
But in terms of "what kind of PC hardware do I need?". There's no
closed-form answer to that question. There's no
handy-dandy "engineering worksheet" that tells you how much "grunt"
you need for different DSP "flows" at
a given sample-rate--so very much depends on what you're doing, and
how you're doing it. Generally, as you scale up
in sample-rate, you have to scale up in:
o CPU base clock rate
o Memory bandwidth
o Number of CPUs
On Wed, 19 Feb 2025 at 10:17, Marcus D. Leech
patchvonbraun@gmail.com wrote:
On 18/02/2025 19:13, Brendan Horsfield wrote:
Thanks for the suggestion about the noise source -- that's what I
would normally do. Unfortunately I haven't actually purchased the
hardware yet -- I was hoping to clarify this issue before raising
a purchase order.
Perhaps I should follow this up with one of the application
engineers at NI? They might have access to an X310+UBX-160
system that they can use to answer my question directly.
Thanks again for your help in this matter.
Regards,
Brendan.
I actually do work for NI on USRP devices (on a very very very
part-time basis). My X310 is currently elsewhere, and not populated
with a UBX-160.
On Wed, 19 Feb 2025 at 09:55, Marcus D. Leech
<patchvonbraun@gmail.com> wrote:
On 18/02/2025 18:45, Brendan Horsfield wrote:
Yes, I assumed that was the case. However, it is not clear
from the X300 documentation how sharp those filters are.
Can you tell me how wide the transition band is at the lower
sample rates?
To give you some context, I would like to use an X300 (or
X310) with a UBX-160 daughterboard to digitise the entire
2.4 GHz Wi-Fi band, which is 83.5 MHz wide. Ideally I would
like to use a sample rate of 100 Msps to minimise the data
rate between the USRP and the host PC. However, before I do
this I need to be certain that the usable bandwidth at this
sample rate will be greater than 83.5 MHz. Is this
information documented somewhere?
It somewhat depends on the decimation. If the decimation has
a factor of two or 4, the edge roll-off is fairly sharp.
Otherwise,
there's a half-band filter in-place that causes a
less-desirable pass-band.
But I don't know, precisely, what the transition band is in
the "nicer" filter shapes.
If you have an X310+UBX-160, you can always just use a noise
source, and measure it yourself to see if it's appropriate for
your application.
On Tue, 18 Feb 2025 at 23:11, Marcus D Leech
<patchvonbraun@gmail.com> wrote:
There will always be some edge roll off. Decimation
includes filtering and those filters cannot be
infinitely steep.
Sent from my iPhone
On Feb 18, 2025, at 2:12 AM, Brendan Horsfield
<brendan.horsfield@vectalabs.com> wrote:
Hi All,
I have a question about the usable bandwidth of the
X300 USRP / UBX-160 daughterboard combo at sampling
rates below 200 Msps:
As I understand it, the UBX-160 receiver has an analog
(hardware) filter before the ADC that limits the usable
bandwidth to 160 MHz, while the ADC runs at 200 Msps.
Therefore the usable bandwidth is around 80% of the
sample rate.
My question is: What is the usable bandwidth at lower
sampling rates? Does the 80% factor always apply?
For example, if I set the decimation factor to 4, so
that my sampling rate is 50 Msps, does this mean that
the usable bandwidth will be 40 MHz?
Thanks & Regards,
Brendan.
USRP-users mailing list -- usrp-users@lists.ettus.com
To unsubscribe send an email to
usrp-users-leave@lists.ettus.com