I think you mean from the curve that for tx-amplitude as 0.2 and then increasing gain gives you the most linear output compared to all other amplitudes . Am I right?
On Wed, Jun 12, 2013 at 7:45 PM, Dan CaJacob <dan.caja...@gmail.com> wrote: > Sure. Sorry. > > Very Respectfully, > > Dan CaJacob > > > On Wed, Jun 12, 2013 at 1:52 AM, Ian Buckley <i...@ionconcepts.com> wrote: > >> Dan, Any chance you can attach those pictures in a different way and >> resend, I couldn't find a way to view them and I'm curious to see them. >> -Ian >> >> On Jun 11, 2013, at 10:12 PM, Dan CaJacob <dan.caja...@gmail.com> wrote: >> >> There are two parameters that will affect your TX power: digital >> amplitude and RF gain. The digital amplitude sets the amplitude of your >> signal going into the DAC. UHD expects a signal between 0 and 1.0, but to >> keep your output nice and linear, keep your signal amplitude belw 0.2. >> Conversely, 0.02 seems pretty low. RF gain is applied in the aughtercard >> once your signal has been up converted. My practice is to keep the signal >> amplitude at 0.2 max amplitude, then adjust RF gain to control power. >> You'll end up getting less than the max rated power output (e.g. 20 dBm >> for WBX, but you'll have a clean RF signal. >> >> I very recently characterized a WBX across the full range of amplitude >> and gain settings. Here's the result. Note that the non linearity belw a >> gain of about -10 dB is due to the signal power being belw the bottom range >> of the power sensor. >> >> >> And here's a plot for just the 0.2 amplitude curve. >> >> >> >> >> On Tuesday, June 11, 2013, yeran wrote: >> >>> Dear all, >>> >>> I am doing channel estimation in gnu radio narrow-band. I'm collecting >>> data at the receiver side after the time_recov block. It has been through >>> the gr.firdes.root_raised_cosine in the time_recov. But the plot I get is >>> as the figures in the attachment. It looks like the fluctuation of the >>> channel amplitude has some pattern, it looks like signal pulse shaping in >>> there. But doesn't the gr.firdes.root_raised_cosine works as the rrc >>> matched filter, and already take off the pulse shaping? >>> >>> Also, when I do experiment, I found out something strange. According to >>> my understanding, the --tx-amplitude on the transmitter benchmark sets the >>> transmission power. So the bigger the amplitude is, the better performance >>> it should be, since the SNR will be bigger. But in actual experiment, it is >>> totally the opposite way! The amplitude of 0.02, or even 0.002 works better >>> than the default 0.25. Has anyone come across the same problems? >>> >>> Highly appreciate if anyone can give me some suggestions on this! Thanks >>> in advance!! >>> >>> Ada >>> >>> <rrc.png> >>> >>> >> >> >> -- >> Very Respectfully, >> >> Dan CaJacob >> >> _______________________________________________ >> 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 > > -- Regards Karan Talasila
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