On Tue, Feb 15, 2011 at 11:31 AM, Daniel Dekst
<address@hidden> wrote:
Hi, All,
I'm using USRP1 with XCVR2450 daughterboard.
I transmit packets with OFDM modulation as in benchmark_ofdm_tx.py.
Using usrp_fft.py I detect the wave form as
http://www.cse.msu.edu/~huangpe3/music/usrp_fft.png
The two edges are attenuated a lot and there is a spike in the middle (DC offset?)
What are the reasons for them and can I address them by updating firmware or something else to get better waveforms as those obtained from USRP2?
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Yes, you will see a DC offset, but the rest of that looks wrong. You are probably sending too wide of a signal, which is getting hit by the half-band filters.
What is the command-line you are using to set the interpolation rate and number of subcarriers?
Tom
Changing the inerpolation rate changes the (frequency) bandwidth.
I know that higher data rate results in wider bandwidth.
But here the output rate is fixed by DAC 128 MS/s. Why the bandwidth is changing in accordance with the interpolation rate?
Thanks a lot for helping me out!
Regards,
Pei
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