Send USRP-users mailing list submissions to
[email protected]
To subscribe or unsubscribe via the World Wide Web, visit
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
or, via email, send a message with subject or body 'help' to
[email protected]
You can reach the person managing the list at
[email protected]
When replying, please edit your Subject line so it is more specific
than "Re: Contents of USRP-users digest..."
Today's Topics:
1. Receive IQ samples with USRP2 and WBX RF Board (Haenggi Stefan)
2. E100 grc gui status ? (Arthur Petry)
3. Re: Turning off the digital down converter(DDC) in USRP2
(Mike McLernon)
4. UHD mirror stuck (Alexandru Csete)
5. Re: E100 grc gui status ? (Philip Balister)
----------------------------------------------------------------------
Message: 1
Date: Wed, 9 Mar 2011 09:27:47 +0100
From: Haenggi Stefan <[email protected]>
To: "[email protected]" <[email protected]>
Subject: [USRP-users] Receive IQ samples with USRP2 and WBX RF Board
Message-ID:
<81876887ee89b44b8b35fba68bd3eb362746c...@srv-ex-01.intra01.enkom.ch>
Content-Type: text/plain; charset="us-ascii"
Gentlemen,
I am using an USRP2 with a WBX RF board over the UHD interface to receive
"COMPLEX_INT16" IQ baseband samples.
It works very well and I am very happy with the performance of the device.
Analyzing the received IQ data, I noticed the following :
1.) Max IQ receive values
The IQ values (signed 16bit int) seem to clip around -13000 and +13000. Is it
correct that the IQ values have a maximal
range of about -13000 and +13000 ?
2.) Receive gain of WBX RF board
If a set via UHD the receive RF gain of the WBX on minimum (0dB), the IQ values
clip @ RF carrier level of -8dBm
If a set via UHD the receive RF gain of the WBX on maximum (30dB), the IQ
values clip @ RF carrier level of -41dBm
Does that seem to be right ? Or can more RF gain be activated somehow ?
If these levels are right, I will lose a lot of effective IQ bits if I have a
weak RF input signal, as example -80dBm.
3.) Glitch in Timedomain
I noticed each time I receive a batch of IQ samples (example 1000), the value
of IQ samples No 15 to 20 seem to
be around 0, regardless what the RF input signal is. This is independent of
sampling rate.
Is that only my setup ? Or do others see that as well ?
4.) Overall Receive Phasenoise
Has somebody already measured RMS PhaseJitter of the receive path? In which
range is that ? Does it change
significantly by locking the USRP2 to a 10MHz reference with low phasenoise?
Thanks a lot for your support
Stefan
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.ettus.com/pipermail/usrp-users_lists.ettus.com/attachments/20110309/106bdf03/attachment-0001.html>
------------------------------
Message: 2
Date: Wed, 9 Mar 2011 12:20:56 +0100
From: Arthur Petry <[email protected]>
To: [email protected]
Subject: [USRP-users] E100 grc gui status ?
Message-ID:
<[email protected]>
Content-Type: text/plain; charset=ISO-8859-1
Hi All,
I'm considering ordering a E100, but I still have some questions about
its capabilities...
According to
http://code.ettus.com/redmine/ettus/projects/usrpe1xx/wiki/FAQ#How-can-I-build-GRC-with-GNU-Radio
, wxPython is not installed by default.
But it seems that some succeded to built it :
http://www.flickr.com/photos/koenkooi/5297178481/in/photostream/
I have seen that Josh Blum is working to have some pyqt widgets, have
we a fft or a scope working on the E100 yet ?
http://www.ruby-forum.com/topic/1076437#981348
My question : is it possible to have a live fft displayed on the E100
with wxPython or pyQt ? And if not yet, do you think it will be
impossible because of E100 linux/graphics performance ?
(I know we can have a pretty fft displayed in ascii thanks to
rx_samples_to_udp, but I think I would prefer a real GUI ;-) )
Sorry for this newbie question, and thanks if someone could help me about that.
Cheers,
Arthur
------------------------------
Message: 3
Date: Wed, 9 Mar 2011 13:10:29 +0000
From: Mike McLernon <[email protected]>
To: "Song, Mujun CAPT KR USAF AETC AFIT/ENG" <[email protected]>
Cc: "[email protected]" <[email protected]>
Subject: Re: [USRP-users] Turning off the digital down converter(DDC)
in USRP2
Message-ID:
<e3879be9a282cb45aab7ce258a9ae48f071...@exmb-01-ah.ad.mathworks.com>
Content-Type: text/plain; charset="us-ascii"
I still think that you can calculate the SCF of the complex baseband signal,
and that you don't need an RF or IF signal in the first place. The SCF of a
modulated signal shows the periodic correlations of the signal that are induced
by the modulation process. Those periodic correlations should exist in the
signal whether it's at complex baseband or at RF.
Hth,
Mike
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Jason Abele
Sent: Tuesday, March 08, 2011 6:54 PM
To: Song, Mujun CAPT KR USAF AETC AFIT/ENG
Cc: [email protected]
Subject: Re: [USRP-users] Turning off the digital down converter(DDC) in USRP2
> I'm working with USRP2 and Simulink to analyze the Spectral Correlation
> Function of transmitter signal. I have some problem which comes from
> Digital Down Converter(DDC) of USRP2. Because the SCF analysis is based
> on RF signal or at least IF signal which show positive and negative
> frequency peaks, the digital down conversion made by USRP2 makes the SCF
> analysis impossible. As I know, the DDC is implemented in FPGA. Is there
> any way to bypass the DDC process in USRP2 to get a IF or RF signal? Or
> is there anybody who know how to get IF or RF signal using different
> way? And I have to keep the link between USRP2 and Simulink.
Eventually, with UHD + Simulink, you could use a uhd::tune_request_t
with a policy setting to force the DDC to 0 Hz, effectively disabling
it.
You can simulate this effect by cleverly choosing your requested center
frequency. If you tell me what daughterboard you are using, I can help
you understand the tuning resolution of the daughterboard, and therefore
which frequencies will have 0 Hz DDC settings.
You can also make guesses at it by first trying multiples of 100MHz or
even integer divisors of 100MHz. So try the multiple of 25MHz closest
to your desired frequency, try the multiples of 5MHz, 1MHz
Jason
_______________________________________________
USRP-users mailing list
[email protected]
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
------------------------------
Message: 4
Date: Wed, 9 Mar 2011 15:44:58 +0100
From: Alexandru Csete <[email protected]>
To: [email protected]
Subject: [USRP-users] UHD mirror stuck
Message-ID:
<[email protected]>
Content-Type: text/plain; charset=ISO-8859-1
Greetings,
The UHD mirror on Github seems to be stuck at Feb 16/17.
Alex
------------------------------
Message: 5
Date: Wed, 09 Mar 2011 07:56:54 -0700
From: Philip Balister <[email protected]>
To: Arthur Petry <[email protected]>
Cc: [email protected]
Subject: Re: [USRP-users] E100 grc gui status ?
Message-ID: <[email protected]>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
On 03/09/2011 04:20 AM, Arthur Perry wrote:
> Hi All,
>
> I'm considering ordering a E100, but I still have some questions about
> its capabilities...
>
> According to
> http://code.ettus.com/redmine/ettus/projects/usrpe1xx/wiki/FAQ#How-can-I-build-GRC-with-GNU-Radio
> , wxPython is not installed by default.
>
> But it seems that some succeded to built it :
> http://www.flickr.com/photos/koenkooi/5297178481/in/photostream/
>
> I have seen that Josh Blum is working to have some pyqt widgets, have
> we a fft or a scope working on the E100 yet ?
> http://www.ruby-forum.com/topic/1076437#981348
>
>
> My question : is it possible to have a live fft displayed on the E100
> with wxPython or pyQt ? And if not yet, do you think it will be
> impossible because of E100 linux/graphics performance ?
>
> (I know we can have a pretty fft displayed in ascii thanks to
> rx_samples_to_udp, but I think I would prefer a real GUI ;-) )
>
>
> Sorry for this newbie question, and thanks if someone could help me about
> that.
Answering this question is at the top of my todo list for next week.
There are some issues with cross compiling the python wx and python qt
libraries. Next week, I am going to do some native builds of pyqt and
the other libraries needed to test Josh's qt work, I'll post an update
when I have more information.
Philip
------------------------------
_______________________________________________
USRP-users mailing list
[email protected]
http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
End of USRP-users Digest, Vol 7, Issue 16
*****************************************
