Well, that is super awesome news 😊

 

Glad you guys made these improvements.

 

How would I know this, I don’t think I have seen this information anywhere?

 

From: Michael West <michael.w...@ettus.com> 
Sent: Thursday, April 19, 2018 9:21 PM
To: Stanley, John P. <john.stan...@jhuapl.edu>
Cc: ROBIN TORTORA <ti...@comcast.net>; Stanley, John P. via USRP-users 
<usrp-users@lists.ettus.com>
Subject: Re: [USRP-users] DC Offset Calibration Issue for Rev. C UBX-40 
daughter cards

 

Hi John/Robin:

The calibration utilities rely on leakage across the RF switch.  The newer UBX 
boards (rev C and later) have RF switches with much higher isolation.  The 
benefit is a lot less leakage from TX onto RX.  The drawback is that the 
calibration utilities will only work if you connect the TX/RX to the RX2 port 
with a 30 dB attenuator in line.

Regards,

Michael

 

On Thu, Apr 19, 2018 at 11:12 AM, Stanley, John P. via USRP-users 
<usrp-users@lists.ettus.com <mailto:usrp-users@lists.ettus.com> > wrote:

While uncalibrated LO leakage has never been great in the UBX for us, the dc 
offset calibration procedure has given us adequate enough improvement.  We’re 
generally using offset tuning, but we still need that extra 15-20 dB 
suppression we get from the calibration procedure.

The issue we’re seeing with these newer Rev C boards, though, is that the 
calibration doesn’t just fail to improve LO suppression; it actively makes it 
worse. Offset tuning is pretty fruitless when the LO spur alone is >0 dBm at 
the mid-point of available RF gain. 

 

 

From: ROBIN TORTORA <ti...@comcast.net <mailto:ti...@comcast.net> >
Reply-To: ROBIN TORTORA <ti...@comcast.net <mailto:ti...@comcast.net> >
Date: Thursday, April 19, 2018 at 1:44 PM
To: "Stanley, John P. via USRP-users" <usrp-users@lists.ettus.com 
<mailto:usrp-users@lists.ettus.com> >, "Stanley, John P." 
<john.stan...@jhuapl.edu <mailto:john.stan...@jhuapl.edu> >
Subject: Re: [USRP-users] DC Offset Calibration Issue for Rev. C UBX-40 
daughter cards

 


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