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 > 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> 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> >> To: "Discuss-gnuradio@gnu.org" <discuss-gnuradio@gnu.org> >> Subject: [Discuss-gnuradio] Max Output Power from the LFTX >> daughterboard >> Message-ID: >> <CACdmG=zCHATiwrtv=wBVLwG0_ >> 5GQr0y=wksequrcajrtuv5...@mail.gmail.com> >> 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" <mle...@ripnet.com> >> To: discuss-gnuradio@gnu.org >> Subject: Re: [Discuss-gnuradio] Max Output Power from the LFTX >> daughterboard >> Message-ID: <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 Consortiumhttp://www.sbrac.org >> >> > > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > >
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