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 On Tue, Jan 6, 2015 at 2:38 PM, Michael Rahaim <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> 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 >> >> >
_______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
