I see. Is there someone we can contact at Ettus for this? Khalid
On Fri, Jan 16, 2015 at 4:29 PM, Marcus D. Leech <[email protected]> wrote: > On 01/16/2015 02:54 PM, khalid.el-darymli wrote: > > I see. If you would like to diagnose the problem, we can ship you the > malfunctioned daughterboard? > > Thanks, > Khalid > > Thanks. I personally wouldn't have time/equipment to really diagnose > it. So it would be up to Ettus R&D as to whether they want it back to see > what the failure mode is. > > I've been doing Ettus support for 6 years, and LF_TX are not generally > items that show up with RMA requests very often. > > > > > On Fri, Jan 16, 2015 at 4:17 PM, Marcus D. Leech <[email protected]> > wrote: > >> On 01/16/2015 02:42 PM, khalid.el-darymli wrote: >> >> We were using only one Tx channel with the Subdev Spec in the USRP Sink >> is set to A:AB >> >> Could the failure be due to that the other (idle) Tx channel is left >> open circuit (i.e., not terminated by 50 ohms)? >> >> That seems quite unlikely. These aren't "precious princess" RF power >> transistors, but reasonably-robust differential-to-unbalanced drivers. I'd >> be very surprised if they couldn't handle an open-circuit condition. >> >> >> >> >> >> Khalid >> >> >> On Fri, Jan 16, 2015 at 3:41 PM, Marcus D. Leech <[email protected]> >> wrote: >> >>> 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 <[email protected]> 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 < >>>> [email protected]> 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 <[email protected]> >>>>> 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" <[email protected]> >>>>>> To: "[email protected]" <[email protected]> >>>>>> Subject: [Discuss-gnuradio] Max Output Power from the LFTX >>>>>> daughterboard >>>>>> Message-ID: >>>>>> <CACdmG=zCHATiwrtv=wBVLwG0_ >>>>>> [email protected]> >>>>>> Content-Type: text/plain; charset="utf-8" >>>>>> >>>>>> 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 >>>>>> -------------- next part -------------- >>>>>> An HTML attachment was scrubbed... >>>>>> URL: < >>>>>> http://lists.gnu.org/archive/html/discuss-gnuradio/attachments/20150106/37846ff4/attachment.html >>>>>> > >>>>>> >>>>>> ------------------------------ >>>>>> >>>>>> Message: 3 >>>>>> Date: Tue, 06 Jan 2015 08:48:08 -0500 >>>>>> From: "Marcus D. Leech" <[email protected]> >>>>>> To: [email protected] >>>>>> Subject: Re: [Discuss-gnuradio] Max Output Power from the LFTX >>>>>> daughterboard >>>>>> Message-ID: <[email protected]> >>>>>> 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 Consortiumhttp://www.sbrac.org >>>>>> >>>>>> >>>>> >>>>> >>>>> >>>>> _______________________________________________ >>>>> Discuss-gnuradio mailing list >>>>> [email protected] >>>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>>>> >>>>> >>>> >>> >>> >>> >>> >> >> >> - >> >> >> > > > > > >
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