USRP1 waveform

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?

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

On Tue, Feb 15, 2011 at 11:31 AM, Daniel D. [email protected]
wrote:

or something else to get better waveforms as those obtained from USRP2?

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

This forum is not affiliated to the Ruby language, Ruby on Rails framework, nor any Ruby applications discussed here.

| Privacy Policy | Terms of Service | Remote Ruby Jobs