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Today's Topics:
1. Re: Transverters (Alex Gladd)
2. Re: Transverters (Alex Gladd)
3. Large Spur produced by SBX transmitter (Briggs, Elliot)
4. Re: Large Spur produced by SBX transmitter (Marcus D. Leech)
5. Re: Large Spur produced by SBX transmitter (Matt Ettus)
6. Re: Testbench for usrp2 (Purush)
7. FPGA problem with a B100 (D led off) (Federico Larroca)
8. Re: FPGA problem with a B100 (D led off) (Marcus D. Leech)
----------------------------------------------------------------------
Message: 1
Date: Thu, 23 May 2013 18:24:43 -0400
From: "Alex Gladd" <[email protected]>
To: "'Mark McCarron'" <[email protected]>,
<[email protected]>
Subject: Re: [USRP-users] Transverters
Message-ID: <005f01ce5804$5365b150$fa3113f0$@com>
Content-Type: text/plain; charset="us-ascii"
I've heard of people reporting success with this one:
http://www.nooelec.com/store/ham-it-up-v1-0-rf-upconverter-for-software-defi
ned-radio.html
They also sell it on Amazon. Oh, it's also open source hardware J
~Alex
From: Mark McCarron [mailto:[email protected]]
Sent: Thursday, May 23, 2013 6:45 AM
To: [email protected]
Subject: [USRP-users] Transverters
What transverter options are their for the WBX boards?
I've seen one that adds 60MHz in a video, but the I can't find any details
on it.
Regards,
Mark McCarron
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Message: 2
Date: Thu, 23 May 2013 18:27:16 -0400
From: "Alex Gladd" <[email protected]>
To: "'Alex Gladd'" <[email protected]>, "'Mark McCarron'"
<[email protected]>, <[email protected]>
Subject: Re: [USRP-users] Transverters
Message-ID: <006401ce5804$ae875020$0b95f060$@com>
Content-Type: text/plain; charset="us-ascii"
Hmm. on second thought, I don't think that one will downconvert for
transmitting, so it may not fit your needs.
~Alex
From: Alex Gladd [mailto:[email protected]]
Sent: Thursday, May 23, 2013 6:25 PM
To: 'Mark McCarron'; '[email protected]'
Subject: RE: [USRP-users] Transverters
I've heard of people reporting success with this one:
http://www.nooelec.com/store/ham-it-up-v1-0-rf-upconverter-for-software-defi
ned-radio.html
They also sell it on Amazon. Oh, it's also open source hardware J
~Alex
From: Mark McCarron [mailto:[email protected]]
Sent: Thursday, May 23, 2013 6:45 AM
To: [email protected]
Subject: [USRP-users] Transverters
What transverter options are their for the WBX boards?
I've seen one that adds 60MHz in a video, but the I can't find any details
on it.
Regards,
Mark McCarron
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Message: 3
Date: Thu, 23 May 2013 23:08:10 +0000
From: "Briggs, Elliot" <[email protected]>
To: "[email protected]" <[email protected]>
Subject: [USRP-users] Large Spur produced by SBX transmitter
Message-ID:
<[email protected]>
Content-Type: text/plain; charset="us-ascii"
Hello mailing list,
I'm using a USRP N210 with an SBX daughtercard to transmit some test signals. I
ran the calibration procedure for IQ imbalance and DC offset, yet I still see a
spur that rises 40 dB from the noise floor centered at the carrier frequency.
My testing is performed using a spectrum analyzer as well as another USRP
N210/SBX. The spur doesn't vary with time or tuning frequency.
I've tried several USRPs and daughtercards with the same results. I've shifted
frequencies to other bands, but the spur never goes away. I've noticed that the
datasheet for the ADL5375 device (U18) in the transmit chain says the RF out
pin must be AC coupled, but the schematic shows a DC path to ground through R37
and R34.
The spur is so large that I've found it necessary to shift the frequency center
of my signal, requiring me to double the D/A sampling rate.
Does anyone else see such a large spur?
Thanks,
Elliot Briggs
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Message: 4
Date: Thu, 23 May 2013 19:38:31 -0400
From: "Marcus D. Leech" <[email protected]>
To: [email protected]
Subject: Re: [USRP-users] Large Spur produced by SBX transmitter
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"
On 05/23/2013 07:08 PM, Briggs, Elliot wrote:
>
> Hello mailing list,
>
> I'm using a USRP N210 with an SBX daughtercard to transmit some test
> signals. I ran the calibration procedure for IQ imbalance and DC
> offset, yet I still see a spur that rises 40 dB from the noise floor
> centered at the carrier frequency. My testing is performed using a
> spectrum analyzer as well as another USRP N210/SBX. The spur doesn't
> vary with time or tuning frequency.
>
> I've tried several USRPs and daughtercards with the same results. I've
> shifted frequencies to other bands, but the spur never goes away. I've
> noticed that the datasheet for the ADL5375 device (U18) in the
> transmit chain says the RF out pin must be AC coupled, but the
> schematic shows a DC path to ground through R37 and R34.
>
> The spur is so large that I've found it necessary to shift the
> frequency center of my signal, requiring me to double the D/A sampling
> rate.
>
> Does anyone else see such a large spur?
>
> Thanks,
>
> Elliot Briggs
>
There will always be some residual LO leakage -- are you running near
MAX TX gain? Try backing off a bit.
Also, offset tuning is supported on TX as well as RX, so you can offset
the LO away from your band center by quite a bit.
--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org
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Message: 5
Date: Thu, 23 May 2013 17:39:32 -0700
From: Matt Ettus <[email protected]>
To: "Briggs, Elliot" <[email protected]>
Cc: "[email protected]" <[email protected]>
Subject: Re: [USRP-users] Large Spur produced by SBX transmitter
Message-ID:
<CAN=1kn--H+FHQwZcx3=kTLNaq1k=ydqo+k5mvshngme06-x...@mail.gmail.com>
Content-Type: text/plain; charset="windows-1252"
Elliot,
There will always be some DC leakage, but this is not affected by the AC
coupling you mentioned. It is a natural result of using direct conversion
architectures. What is the absolute power level of this spur? 40dB above
the noise floor doesn't tell me, because that is dependent on your
instrument and settings. I think you will find that the actual power in
this tone is much lower than the power in your desired signal, and so will
not be an issue.
Incidentally, this is exactly why most OFDM standards don't use the middle
tone in their spectrum, since it is difficult to bring the DC tone down
much below -40 to -50 dBc.
Matt
On Thu, May 23, 2013 at 4:08 PM, Briggs, Elliot <[email protected]>wrote:
> Hello mailing list,****
>
> ** **
>
> I?m using a USRP N210 with an SBX daughtercard to transmit some test
> signals. I ran the calibration procedure for IQ imbalance and DC offset,
> yet I still see a spur that rises 40 dB from the noise floor centered at
> the carrier frequency. My testing is performed using a spectrum analyzer as
> well as another USRP N210/SBX. The spur doesn?t vary with time or tuning
> frequency.****
>
> ** **
>
> I?ve tried several USRPs and daughtercards with the same results. I?ve
> shifted frequencies to other bands, but the spur never goes away. I?ve
> noticed that the datasheet for the ADL5375 device (U18) in the transmit
> chain says the RF out pin must be AC coupled, but the schematic shows a DC
> path to ground through R37 and R34. ****
>
> ** **
>
> The spur is so large that I?ve found it necessary to shift the frequency
> center of my signal, requiring me to double the D/A sampling rate. ****
>
> ** **
>
> Does anyone else see such a large spur?****
>
> ** **
>
> Thanks,****
>
> Elliot Briggs****
>
> _______________________________________________
> USRP-users mailing list
> [email protected]
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>
>
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Message: 6
Date: Fri, 24 May 2013 15:29:26 +0200
From: Purush <[email protected]>
To: [email protected]
Subject: Re: [USRP-users] Testbench for usrp2
Message-ID:
<caouk5sbeuf02s9xncvqizjvfvhik28v_r6q9ch12dhru1oe...@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
I was able to fix the testbench issue. The problem was in the
initialization of with the 'ram_loader.v'. There was a single bit
shift when the program file was loaded in to the design. I played with
the clock of the 'single_u2_sim.v' design. (As i didn't want too many
changes in the actual design itself)
I finally edited the 'aux_clk' to:
always #12 aux_clk = ~aux_clk;
This corrected the problem.
Now the design has my custom registers connected to settings_reg. The
reading of this register is enabled by connecting the outputs of the
register to an empty space in the readback_mux.
I want to read the registers from the host machine. 'multi_usrps.hpp'
has a function to write the register ...which goes something like
'usrp->set_user_register(240,0,0);'
Now the question is : how do I read the register connected to the
'readback_mux' from the host machine?
Is there any simple example c file that demonstrate read (from readback_mux) ?
The peek32() and poke32() methods are not there in the 'multi_usrps.hpp'
On Wed, May 15, 2013 at 11:20 AM, Purush <[email protected]> wrote:
> I am USRP newbie. I am trying to get a first hands on experience in adding
> few registers into the FPGA and reading them back into the host machine.
>
> I am using USRP2 and using the main branch of UHD.
>
> To start with I am just adding registers into the "u2_core.v" and making
> changes into the firmware of ZPU. I added to the code to write
> "sr_my_regs_ctrl->params_b = 0xffffffff;" to the zpu code (in the u2_init.c
> file) and generated the rom file. As described in :
>
> http://lists.ettus.com/pipermail/usrp-users_lists.ettus.com/2011-March/000886.html
>
> I renamed the generated ROM file to "flash.rom" and moved it to the
> testbench folder.
>
> I am using a mixed language simulator (i.e. ModelSim) to simulate the design
> and see the register being written. I understand that the testbench found in
> the "testbench/single_u2_sim.v" is outdated and needs to be changed to
> remove some obvious library errors generated due to FIFO libraries. As
> discussed in the message exchanges by the post:
>
> http://lists.ettus.com/pipermail/usrp-users_lists.ettus.com/2012-January/003305.html
>
> I do ensure that the "flash.rom" is read properly. I ran the simulation to
> 4000 us and yet the registers "sr_my_regs_ctrl->params_b" are not written
> neither the LED registers show any changes.
>
> Where is that I have gone wrong? Am I following the right steps here?
>
>
------------------------------
Message: 7
Date: Fri, 24 May 2013 12:20:40 -0300
From: Federico Larroca <[email protected]>
To: [email protected]
Subject: [USRP-users] FPGA problem with a B100 (D led off)
Message-ID:
<CAHe2E1JaeEp8L-Pk=bg_gr7j7+vejhoobfxq3qbrnpp3fsm...@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"
Hi everyone,
Here in the lab we have been working with several USRPs for some months
now. In particular we got a couple of B100+WBX bundles some months ago, and
we had them working perfectly fine until yesterday. Suddenly, we got the
dreaded "KeyError: No devices found for ----->" error with one of them.
Moreover, uhd_find_devices returns a "No UHD Devices Found".
Since the D led is not on, we assume there is a problem with FPGA image.We
have tested the USRP with other PCs to no avail. It is important to
highlight that the other B100+WBX bundle do work.
Any suggestions? Maybe the solution is to send the faulty USRP to the
official "service" but we wanted to verify if we could repair it in our
own.
Thanks in advance,
Federico
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Message: 8
Date: Fri, 24 May 2013 11:27:51 -0400
From: "Marcus D. Leech" <[email protected]>
To: [email protected]
Subject: Re: [USRP-users] FPGA problem with a B100 (D led off)
Message-ID: <[email protected]>
Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"
On 05/24/2013 11:20 AM, Federico Larroca wrote:
> Hi everyone,
> Here in the lab we have been working with several USRPs for some
> months now. In particular we got a couple of B100+WBX bundles some
> months ago, and we had them working perfectly fine until yesterday.
> Suddenly, we got the dreaded "KeyError: No devices found for ----->"
> error with one of them. Moreover, uhd_find_devices returns a "No UHD
> Devices Found".
> Since the D led is not on, we assume there is a problem with FPGA
> image.We have tested the USRP with other PCs to no avail. It is
> important to highlight that the other B100+WBX bundle do work.
> Any suggestions? Maybe the solution is to send the faulty USRP to the
> official "service" but we wanted to verify if we could repair it in
> our own.
> Thanks in advance,
> Federico
>
>
> _______________________________________________
> USRP-users mailing list
> [email protected]
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
What does "lsusb" show when you plug the faulty device in?
Since other B100s work on the same PC, the FPGA image on the PC is
fine--the FPGA image gets re-loaded over the USB every time it needs to--
like across power-cycles, etc.
--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org
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