>>Currently, what I'm doing is keep the tx-amplitude 0.2, and change the gain from 35 to 65. You mean in this range, the power is not liner to gain change, right? If so, is there any way to control or influence the power change? I was mentioning about the that total Tx-Power. U can control Tx-power by varing the value of tx-dsp-amplitude from 0-1 in daughter-boards that don't have variable tx-gain e.g. RFX2400 otherwise its the combination of both tx-dsp-amplitude and tx-gain.
-Adeel On Thu, Jul 25, 2013 at 9:10 PM, yeran <yeran0...@hotmail.com> wrote: > Hi Adeel, > > Thanks for your prompt reply! > > I don't quite understand your last email. If I want to test the > performance of transmission under different power allocation. What should I > do? Can you please be more specific about this? > > Currently, what I'm doing is keep the tx-amplitude 0.2, and change the > gain from 35 to 65. You mean in this range, the power is not liner to gain > change, right? If so, is there any way to control or influence the power > change? > > Thank you! > > Regards, > Ada > > ------------------------------ > Date: Wed, 24 Jul 2013 06:12:15 +0500 > Subject: Re: [Discuss-gnuradio] how to raise the packet error rate in > benchmark > From: adeela...@gmail.com > To: yeran0...@hotmail.com; discuss-gnuradio@gnu.org > > > Ada, > > >>once the signal has been up converted. Now I'm using 0.2 amplitude and > 35 gain. But I don't understand, how come that the smaller the power is, > the better transmission performance there will be. And also, why does power > should be in the range of 0 to 1.0? How to calculate transmission power > using the -tx-amplitude and tx-gain? > Better performance is not due to smaller power but it is due to the > non-linear effects of RF-amplifiers. As per my observations, Tx-Dsp > amplitude beyond 0.15 to 0.2 causes the USRP daughter-boards > Tx-amplification-stage to go into non-linear region thus error-rate of > PSK/QAM increases. Non-linear modulation e.g. FSK/GMSK are more robust to > Amps non-linear effects. so u can experiment increasing TX-amplitude both > for FSK-variants & PSK/QAM and observe performance. > > -Adeel > > > On Tue, Jul 23, 2013 at 9:25 PM, yeran <yeran0...@hotmail.com> wrote: > > Hi everyone, > > I'm doing a project on joint decode. But my problem is that in the lab > environment, the benchmark transmission is always good, there are hardly > any packet loss, so I can not show the advantage of joint decode. > > I've tried to change the physical distance from transmission to receiver > attenna. Still works really well even put in opposite side of the building. > > I've tried to change the transmission power and transmission rate. > Inspired by some previous study, I learned that transmission power is > controlled by -tx-amplitude and -tx-gain, in which -tx-amplitude sets the > amplitude of the signal going into the DAC. RF gain is applied in the > daughtercard once the signal has been up converted. Now I'm using 0.2 > amplitude and 35 gain. But I don't understand, how come that the smaller > the power is, the better transmission performance there will be. And also, > why does power should be in the range of 0 to 1.0? How to calculate > transmission power using the -tx-amplitude and tx-gain? > > Is there any other way that may cause more error in transmission beside > the ones I mentioned? > > Thanks in advance! Any suggestion will be greatly appreciated! > > Ada > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > >
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