[USRP-users] TVRX2 Automatic Gain Control problem

Marcus D. Leech mleech at ripnet.com
Wed Jun 20 17:31:15 EDT 2012

> Greetings,
> I'm working on a project using two USRP1 Rev. 4.5 (both USRP1 works 
> separately) and four TVRX2 Rev. 1.1 boards for DF application.
> Besides the phase alignment, this application needs the implementation 
> of amplitude detection on all RX channels too, and for this goal, the 
> Automatic Gain Control could screw up the real value of amplitude from 
> the received signals.
> Can the AGC feature on the TVRX2 receivers be shut down or manually 
> adjusted across the software configurations or hardware modifications ?
No, there is no way to turn off the AGC on the TVRX2.  This has been 
thoroughly investigated at Ettus, and it cannot be done.

> Another question, i don't had success to find the full datasheet of 
> TDA18272 receiver on the internet, even at manufacturer's website. I 
> only had found a shorten version of datasheet with 10 pages that shows 
> superficially the IC's features. Do you have and could you send me a 
> copy of full datasheet or application notes of TDA18272 receiver used 
> on TVRX2 design ?
> I thanks for your attention, knowing your time is precious.
The full datasheet is available only under NDA with NXP.

Also, keep in mind that only a *single* TVRX2 can be used per USRP1 due 
to I2C addressing limitations.

Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium

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