On 01/16/2015 02:08 PM, khalid.el-darymli wrote:
Hi All,
Just to update you in case somebody else comes across this problem.
Following Mike's advice, we replaced the LFTX daughterboard with a new
one. We're getting now 1 V p-p. This is around 4 dBm.
Thanks very much for your help.
Best regards,
Khalid
Interesting. The driver chip that's used, as a unity-gain
differential-to-single-ended driver, is, according to the datasheets,
pretty robust. So, it would
be interesting to know exactly what the failure mode is.
On Tue, Jan 6, 2015 at 2:38 PM, Michael Rahaim <mrah...@bu.edu
<mailto:mrah...@bu.edu>> wrote:
Hi Khalid,
I had a similar issue with an LFTX that I had been working with
for about two years. I actually had two boards running on separate
USRP2's and both were working fine for quite a while, but I
recently noticed that one had a drastically lower output range. I
ended up replacing the LFTX and all is working well now, so I'm
assuming it was a hardware issue that came up at some point.
I didn't take the time to look for the problem, but I figured I'd
share this info since what you're seeing might be a hardware issue
rather than something you can resolve with settings.
-Mike
On Tue, Jan 6, 2015 at 12:59 PM, khalid.el-darymli
<khalid.el-dary...@mun.ca <mailto:khalid.el-dary...@mun.ca>> wrote:
>> Output power is determined largely by baseband signal
magnitude in that case.
Yes, I understand. And I noticed that for baseband signal with
an amplitude *> 1, * the pass-band signal gets clipped off. So
I assume that an amplitude of 1 for the baseband signal should
deliver the maximum output power (for the pass-band signal).
My question was, what is the maximum power one can get for the
pass-band signal output from LFTX? In your earlier reply, you
said it is around +7dBm, am I getting this right? In my case,
for a baseband amplitude of around 1, I am only getting
*-28.13dBm*, much less than what you said, I am not sure,*why?*
Thanks,
Khalid
On Tue, Jan 6, 2015 at 1:56 PM, Marcus D. Leech
<mle...@ripnet.com <mailto:mle...@ripnet.com>> wrote:
Thanks Marcus for your reply.
>> Probably somewhere in the neighborhood of +7dBm, maybe a
little more.
>> The LF/BASIC series have *no* gain in either path, so
you're just looked
at buffered ADC ouput.
So, ~ *+7dBm* is the max output power I supposed to get
from the LFTX daughterboard? How do I get that?
Since I am only getting -28.13 dBm, does that mean I have
some issue with my LFTX daughterboard?
Khalid
Output power is determined largely by baseband signal
magnitude in that case.
Message: 2
Date: Tue, 6 Jan 2015 10:13:45 -0330
From: "khalid.el-darymli" <khalid.el-dary...@mun.ca
<mailto:khalid.el-dary...@mun.ca>>
To: "Discuss-gnuradio@gnu.org
<mailto:Discuss-gnuradio@gnu.org>"
<discuss-gnuradio@gnu.org <mailto:discuss-gnuradio@gnu.org>>
Subject: [Discuss-gnuradio] Max Output Power from the LFTX
daughterboard
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Hi,
What is the maximum output power from the LFTX
daughterboard when used with
the USRP N200?
According to this datasheet [1], the N200 with the WBX
daughterbaord
provide an output power of 15 dBm. However, when using
the LFTX
daughterboard, I am getting a much less output power.
[1]
http://www.ettus.com/content/files/07495_Ettus_N200-210_DS_Flyer_HR.pdf
In GNU Radio with the USRP N200, we use a sinusoid with a
frequency of 150
kHz and an amplitude of 0.98, fed into the LFTX
daughterboard for a center
frequency of 5 MHz. When the output of LFTX is plugged
into a scope
terminated with a 50-ohm terminator, the scope reads 24.8 mV
(peak-to-peak). This is around -28.13 dBm.
Is this the max power one can get out of the LFTX
daughterboard?
Thanks.
Best regards,
Khalid
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Message: 3
Date: Tue, 06 Jan 2015 08:48:08 -0500
From: "Marcus D. Leech" <mle...@ripnet.com
<mailto:mle...@ripnet.com>>
To: discuss-gnuradio@gnu.org
<mailto:discuss-gnuradio@gnu.org>
Subject: Re: [Discuss-gnuradio] Max Output Power from the
LFTX
daughterboard
Message-ID: <54abe798.5060...@ripnet.com
<mailto:54abe798.5060...@ripnet.com>>
Content-Type: text/plain; charset=UTF-8; format=flowed
On 01/06/2015 08:43 AM, khalid.el-darymli wrote:
> Hi,
>
> What is the maximum output power from the LFTX
daughterboard when used
> with the USRP N200?
>
> According to this datasheet [1], the N200 with the WBX
daughterbaord
> provide an output power of 15 dBm. However, when using
the LFTX
> daughterboard, I am getting a much less output power.
> [1]
>
http://www.ettus.com/content/files/07495_Ettus_N200-210_DS_Flyer_HR.pdf
>
> In GNU Radio with the USRP N200, we use a sinusoid with
a frequency of
> 150 kHz and an amplitude of 0.98, fed into the LFTX
daughterboard for
> a center frequency of 5 MHz. When the output of LFTX is
plugged into a
> scope terminated with a 50-ohm terminator, the scope
reads 24.8 mV
> (peak-to-peak). This is around -28.13 dBm.
>
> Is this the max power one can get out of the LFTX
daughterboard?
>
>
> Thanks.
>
> Best regards,
> Khalid
Probably somewhere in the neighborhood of +7dBm, maybe a
little more.
The LF/BASIC series have *no* gain in either path, so
you're just looked
at buffered ADC ouput.
--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org
--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org
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