USRP2 WBX DC problem

[jcarlosvgr]

I'm using the USRP2 to sense the TV band. I do sensing in an entire 8 MHz DVB-T channel, the sample rate is 8Ms/s. The samples from USRP are in base band and sometimes appear a glitch at 0 it seems DC power. I've tried some techniques as filter DC power or let run for some time consider stabilization but were not efficient. I'm using a WBX daughterboard. Is there any suggestion?

[ErikL]

Hello -

Can you please take a screen shot of the behavior you are describing and share your VI.  It would also be good to have a better understanding of what you mean by 'glitch' at DC as well.

One possible work-around is to acquire the DVB-T signal off-center at a higher bandwidth (treating it as IF) and then filtered and shifted to baseband for processing.  For example, set the acqusition rate to 20MS/s and place the center frequency to the left of the 8MHz bandwidth DVB-T signal.  The spectrum of interst can then be filtered and recentered to DC using digital signal processing techniques. Related to the USRP2 and WBX Ettus Reserach hardware:  There have been multiple revisions to the WBX daughter board over time and we are unable to support the hardware itself. NI does sell the NI USRP-2920 which incorporates revisions to the WBX.  NI provides hardware support and warranty for NI USRP devices.

Best Regards,

Erik

[jcarlosvgr]

I’ve read you suggestion and I did something similar, I double the band wide and tune the USRP to the beginning of the band minus, I wanted capture then I just ignore the other part.

Thanks for the tip

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@ErikL wrote:

Hello -

Can you please take a screen shot of the behavior you are describing and share your VI.  It would also be good to have a better understanding of what you mean by 'glitch' at DC as well.

One possible work-around is to acquire the DVB-T signal off-center at a higher bandwidth (treating it as IF) and then filtered and shifted to baseband for processing.  For example, set the acqusition rate to 20MS/s and place the center frequency to the left of the 8MHz bandwidth DVB-T signal.  The spectrum of interst can then be filtered and recentered to DC using digital signal processing techniques. Related to the USRP2 and WBX Ettus Reserach hardware:  There have been multiple revisions to the WBX daughter board over time and we are unable to support the hardware itself. NI does sell the NI USRP-2920 which incorporates revisions to the WBX.  NI provides hardware support and warranty for NI USRP devices.

Best Regards,

Erik

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[jcarlosvgr]

I’ve read you suggestion and I did something similar, I double the band wide and tune the USRP to the beginning of the band wanted capture then I just ignore the other part.

Thanks for the tip

---

@ErikL wrote:

Hello -

Can you please take a screen shot of the behavior you are describing and share your VI.  It would also be good to have a better understanding of what you mean by 'glitch' at DC as well.

One possible work-around is to acquire the DVB-T signal off-center at a higher bandwidth (treating it as IF) and then filtered and shifted to baseband for processing.  For example, set the acqusition rate to 20MS/s and place the center frequency to the left of the 8MHz bandwidth DVB-T signal.  The spectrum of interst can then be filtered and recentered to DC using digital signal processing techniques. Related to the USRP2 and WBX Ettus Reserach hardware:  There have been multiple revisions to the WBX daughter board over time and we are unable to support the hardware itself. NI does sell the NI USRP-2920 which incorporates revisions to the WBX.  NI provides hardware support and warranty for NI USRP devices.

Best Regards,

Erik

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