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Today's Topics:
1. Re: B210 FPGA/FW Issue (Ralph A. Schmid, dk5ras)
2. USRP X300/X310 reference daisy-chain (Rob Miller)
3. Re: USRP X300/X310 reference daisy-chain (Michael West)
4. Re: USRP X300/X310 reference daisy-chain (Marcus M?ller)
5. Re: USRP X300/X310 reference daisy-chain (Marcus M?ller)
----------------------------------------------------------------------
Message: 1
Date: Thu, 16 Oct 2014 19:00:25 +0200
From: "Ralph A. Schmid, dk5ras" <[email protected]>
To: "'Ian Buckley'" <[email protected]>, "'hossein talaiee'"
<[email protected]>
Cc: [email protected]
Subject: Re: [USRP-users] B210 FPGA/FW Issue
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"
Well, I _love_ the design of the bladeRF with its SPI flash for both images.
Ralph.
From: USRP-users [mailto:[email protected]] On Behalf Of
Ian Buckley via USRP-users
Sent: Tuesday, October 14, 2014 11:32 PM
To: hossein talaiee
Cc: [email protected]
Subject: Re: [USRP-users] B210 FPGA/FW Issue
Nope. There is non no-volatile memory on the board to store the FPGA
configuration.
This in fact makes the design much easier since handling the update and
fail-safe of stored images is a non-trivial problem.
-Ian
On Oct 14, 2014, at 2:19 PM, hossein talaiee via USRP-users
<[email protected]> wrote:
Why ?
Can't be permanently programmed on board?
On Wed, Oct 15, 2014 at 12:21 AM, Marcus M?ller <[email protected]>
wrote:
Hi Hossein,
these images have to be loaded everytime you reset your device, ie. whenever
you plug it into power; it's not a one-time procedure.
Greetings,
Marcus
On 14.10.2014 22:39, hossein talaiee via USRP-users wrote:
Hi
I have e B210 board with spec:
revision: 4
product: 2
FW Version: 4.0
FPGA Version: 3.0
Each time I want to run examples of UHD like benchmark it start to load
FPGA image and sometimes fw too!
Why this happen? Isn't it a one time procedure ?
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Message: 2
Date: Thu, 16 Oct 2014 18:30:44 -0400
From: Rob Miller <[email protected]>
To: "[email protected]" <[email protected]>
Subject: [USRP-users] USRP X300/X310 reference daisy-chain
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"
Hi -Does anyone know a practical maximum for the number of USRP X300/310s that
can have their references (10MHz/1PPS) daisy-chained together.Best,Rob
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Message: 3
Date: Thu, 16 Oct 2014 17:36:36 -0700
From: Michael West <[email protected]>
To: Rob Miller <[email protected]>
Cc: "[email protected]" <[email protected]>
Subject: Re: [USRP-users] USRP X300/X310 reference daisy-chain
Message-ID:
<CAM4xKroQ8K6aZGpQU2j+6a6Pb+0PjgWBaatCZ=Vfa_8=rwE=k...@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"
Hi Rob,
Characterization of the daisy-chaining for the X3x0s has not been
completed, so it is not possible to say at this time. Officially,
daisy-chaining is not yet supported.
That said, I believe there is buffering on the lines so, in theory, an
unlimited number of devices can be daisy-chained. Some propagation delay
from device to device is expected (varies dependent on cable length), so
the limitation is primarily dependent on how tightly all the devices need
to be synchronized for a particular application. The bottom line is that
daisy-chaining is still experimental, so you will have to try it to see if
it works for you.
Best regards,
Michael E. West
On Thu, Oct 16, 2014 at 3:30 PM, Rob Miller via USRP-users <
[email protected]> wrote:
> Hi -
> Does anyone know a practical maximum for the number of USRP X300/310s that
> can have their references (10MHz/1PPS) daisy-chained together.
> Best,
> Rob
>
>
> _______________________________________________
> USRP-users mailing list
> [email protected]
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>
>
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Message: 4
Date: Fri, 17 Oct 2014 11:55:56 +0200
From: Marcus M?ller <[email protected]>
To: [email protected]
Subject: Re: [USRP-users] USRP X300/X310 reference daisy-chain
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"
Hi Rob,
Michael is right, the Ref out is buffered (it's U530, which is a FIN1002
LVDS->LVTTL converter/buffer), and the signal is basically just an
output of the internal 10MHz clock.
So what you get by daisy chaining is USRPs that shouldn't exhibit
significant frequency offset[1]. What you won't get is
delay-compensation, since the X300 can't know your cable length. Also,
you'll get accumulated error -- which might not be a big problem for the
overall system, because the PLLs generating the ADC clocks on the
motherboards and the LOs on the daughterboards don't have an infinite
control loop bandwidth, which will antagonize random variations of pulse
duration, but it surely won't increase system performance.
Personally, I find daisy chaining to be an awesome concept when it comes
to synchronizing "a few" devices, because you can do that without an
external clock distributor, knowing that errors introduced can't be that
serious. When it comes to synchronizing a lot of devices, I'd say a
clock distributor is the easiest way to go, on the fact alone that you
can take out any X300 without breaking clocking.
So, as usual, I'm curious [2], so: what setup do you have in mind?
Greetings,
Marcus
[1] let's assume, for gross simplification, that you're not moving the
x300s relative to each other at high speeds while having them connected
via coax, so we can neglect Doppler ;)
[2] ok. I'm a nerd. Stuff me in a room with a rack full of cool devices
and I'm happy for a while. That might explain the curiosity when it
comes to connecting numbers of X300s...
On 17.10.2014 02:36, Michael West via USRP-users wrote:
> Hi Rob,
>
> Characterization of the daisy-chaining for the X3x0s has not been
> completed, so it is not possible to say at this time. Officially,
> daisy-chaining is not yet supported.
>
> That said, I believe there is buffering on the lines so, in theory, an
> unlimited number of devices can be daisy-chained. Some propagation delay
> from device to device is expected (varies dependent on cable length), so
> the limitation is primarily dependent on how tightly all the devices need
> to be synchronized for a particular application. The bottom line is that
> daisy-chaining is still experimental, so you will have to try it to see if
> it works for you.
>
> Best regards,
> Michael E. West
>
> On Thu, Oct 16, 2014 at 3:30 PM, Rob Miller via USRP-users <
> [email protected]> wrote:
>
>> Hi -
>> Does anyone know a practical maximum for the number of USRP X300/310s that
>> can have their references (10MHz/1PPS) daisy-chained together.
>> Best,
>> Rob
>>
>>
>> _______________________________________________
>> USRP-users mailing list
>> [email protected]
>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>>
>>
>
>
> _______________________________________________
> USRP-users mailing list
> [email protected]
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
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Message: 5
Date: Fri, 17 Oct 2014 12:13:18 +0200
From: Marcus M?ller <[email protected]>
To: [email protected]
Subject: Re: [USRP-users] USRP X300/X310 reference daisy-chain
Message-ID: <[email protected]>
Content-Type: text/plain; charset=ISO-8859-1
One thing I forgot to mention: the ref clock signal goes through a
jitter cleaner, which should reduce errors when daisy-chaining. (it's an
LMK04816, if you want to look up the datasheet).
Marcus
On 17.10.2014 11:55, Marcus M?ller wrote:
> Hi Rob,
>
> Michael is right, the Ref out is buffered (it's U530, which is a FIN1002
> LVDS->LVTTL converter/buffer), and the signal is basically just an
> output of the internal 10MHz clock.
> So what you get by daisy chaining is USRPs that shouldn't exhibit
> significant frequency offset[1]. What you won't get is
> delay-compensation, since the X300 can't know your cable length. Also,
> you'll get accumulated error -- which might not be a big problem for the
> overall system, because the PLLs generating the ADC clocks on the
> motherboards and the LOs on the daughterboards don't have an infinite
> control loop bandwidth, which will antagonize random variations of pulse
> duration, but it surely won't increase system performance.
>
> Personally, I find daisy chaining to be an awesome concept when it comes
> to synchronizing "a few" devices, because you can do that without an
> external clock distributor, knowing that errors introduced can't be that
> serious. When it comes to synchronizing a lot of devices, I'd say a
> clock distributor is the easiest way to go, on the fact alone that you
> can take out any X300 without breaking clocking.
>
> So, as usual, I'm curious [2], so: what setup do you have in mind?
>
> Greetings,
> Marcus
>
> [1] let's assume, for gross simplification, that you're not moving the
> x300s relative to each other at high speeds while having them connected
> via coax, so we can neglect Doppler ;)
> [2] ok. I'm a nerd. Stuff me in a room with a rack full of cool devices
> and I'm happy for a while. That might explain the curiosity when it
> comes to connecting numbers of X300s...
> On 17.10.2014 02:36, Michael West via USRP-users wrote:
>> Hi Rob,
>>
>> Characterization of the daisy-chaining for the X3x0s has not been
>> completed, so it is not possible to say at this time. Officially,
>> daisy-chaining is not yet supported.
>>
>> That said, I believe there is buffering on the lines so, in theory, an
>> unlimited number of devices can be daisy-chained. Some propagation delay
>> from device to device is expected (varies dependent on cable length), so
>> the limitation is primarily dependent on how tightly all the devices need
>> to be synchronized for a particular application. The bottom line is that
>> daisy-chaining is still experimental, so you will have to try it to see if
>> it works for you.
>>
>> Best regards,
>> Michael E. West
>>
>> On Thu, Oct 16, 2014 at 3:30 PM, Rob Miller via USRP-users <
>> [email protected]> wrote:
>>
>>> Hi -
>>> Does anyone know a practical maximum for the number of USRP X300/310s that
>>> can have their references (10MHz/1PPS) daisy-chained together.
>>> Best,
>>> Rob
>>>
>>>
>>> _______________________________________________
>>> USRP-users mailing list
>>> [email protected]
>>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>>>
>>>
>>
>> _______________________________________________
>> USRP-users mailing list
>> [email protected]
>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>
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