RX Gain (UHD vs libusrp2)

Hi all,
I’m in the process to migrate our software currently using the old
libusrp2 to use the UHD.
My daughter board of reference is the WBX.
With the libusrp2 the gain range was [0, 31.5] while with UHD is [0,
38].
I have noticed that now with UHD is possible to set (apart the overall
gain chain) the gain for the following elements:

WBX-PGA0 with a range [0.0, 31.5]
ADC-digital with a range [0.0, 6.0]
ADC-digital-fine with a range [0.0, 0.5]

this means that using the libusrp2 those two ADC gains were set to 6.0
and 0.5 giving then the user the ability
to change only the WBX-PGA0?

Even setting ADC-digital = 6.0, ADC-digital-fine = 0.5 and setting the
WBX-PGA0 to same value used with libusrp2
the result is not the same as in I’m losing something like 20 dB.
Is this expected ?

Regards
Gaetano M.


Even setting ADC-digital = 6.0, ADC-digital-fine = 0.5 and setting the
WBX-PGA0 to same value used with libusrp2
the result is not the same as in I’m losing something like 20 dB.
Is this expected ?

Missing 20dB sounds like maybe you have the other antenna port
selected. Have you tried swapping antenna ports or using a call to
set_rx_antenna() to explicitly select your antenna port?

Jason

On Mon, Mar 28, 2011 at 2:02 PM, Jason A. [email protected] wrote:

Even setting ADC-digital = 6.0, ADC-digital-fine = 0.5 and setting the
WBX-PGA0 to same value used with libusrp2
the result is not the same as in I’m losing something like 20 dB.
Is this expected ?

Missing 20dB sounds like maybe you have the other antenna port
selected. Have you tried swapping antenna ports or using a call to
set_rx_antenna() to explicitly select your antenna port?

You were right, indeed without the set_rx_antenna the selected antenna
was RX2 while I have connected the TX/RX, using the set_rx_antenna to
TX/RX I’m getting now the expected powers.

If I have to use the device as receive only do you suggest to use the
RX2
connection ?

Regards
Gaetano mendola


cpp-today.blogspot.com

On 28/03/2011 10:02 AM, Jason A. wrote:

Even setting ADC-digital = 6.0, ADC-digital-fine = 0.5 and setting the
WBX-PGA0 to same value used with libusrp2
the result is not the same as in I’m losing something like 20 dB.
Is this expected ?
Missing 20dB sounds like maybe you have the other antenna port
selected. Have you tried swapping antenna ports or using a call to
set_rx_antenna() to explicitly select your antenna port?

Jason
Also, the USRP2 has no VGA in front of the ADC – the only gain control
you have is the WBX itself, which is a total range of 31.5dB, AFAIR.

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