Dear Zealdeal, you should know how OFDM works: An OFDM symbol is nothing more than the IDFT of a vector of permutated, possibly padded symbols. No, for the sake of a simple example, assume your symbol vector is [1,1,1,...,1]; without doubt, you'll notice that the IDFT of that vector has an entry that exhibits a magnitude much larger than 1, whilst the other elements of the IDFT have a much smaller magnitude (should be 0!). This uneven distribution of power in time domain is a problem so common to all OFDM systems that there is a fixed term coined for that: the PAPR (peak/average power ratio); I'm pretty sure that you've stumbled across that in whatever introduced you to OFDM.
Best regards, Marcus On 02/17/2015 08:21 AM, zealdeal wrote: > I'm bit confused here. > > You said "In the OFDM example, watch the amplitude of the signal before it > enters the USRP sink. If it exceeds 1.0, I promise it will clip" > > I transmitted OFDM symbols, keeping transmission amplitude as 0.2 > > Then, on the collected log, I ran gr_plot_ofdm.py tool. It shows the plot of > transmitted signal in time domain. > > I see that the amplitude is much more than 1 in that plot. > > Could please tell me where am I going wrong? > > > > -- > View this message in context: > http://gnuradio.4.n7.nabble.com/Amplitude-settings-in-uhd-siggen-tp52274p52337.html > Sent from the GnuRadio mailing list archive at Nabble.com. > > _______________________________________________ > 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
