[USRP-users] USRP N210 WBX Board | ADF 4350 VCO IC Not getting Configured

Marcus D. Leech mleech at ripnet.com
Wed Nov 15 23:09:13 EST 2017

On 11/15/2017 08:27 PM, Rohit Kulkarni via USRP-users wrote:
> Hi,
> I am working on USRP N210 with a WBX (Revision 2) daughterboard. The 
> WBX daughterboard uses ADF 4350 to generate a frequency signal which 
> feeds into the mixer in the RX chain.
> We want to have a control over the frequency signal generated by ADF 
> 4350 (this is a differential signal available on pins RFOut A+/-) and 
> hence we have erased the connection between CPout pin to Vtune pin and 
> feed a constant (or varying) voltage signal to Vtune pin. (This signal 
> is generated externally through say a voltage power supply). We then 
> run uhd_fft -f <some frequency> to set up the default register values 
> within ADF 4350 and try to feed a voltage signal of constant or 
> varying magnitude between 0.5V to 2.4V.
> When we monitor the frequency signal coming out of RFOutA+/- we see 
> that it's a constant frequency signal which varies only when we run 
> uhd_fft with a different frequency setting. Frequency signal does not 
> vary as we sweep our voltage signal (feeding to Vtune) from 0.5V to 2.4V.
> Assuming that all the connections are proper and we are feeding a 
> valid voltage signal to Vtune, can someone tell me what might be going 
> wrong possibly in our setup?
> For your reference, this is the schematic of the WBX daughterboard 
> (check page 3) - https://files.ettus.com/schematics/wbx/WBX.pdf
> Datasheet of ADF 4350 - 
> http://www.analog.com/media/en/technical-documentation/data-sheets/ADF4350.pdf
> Thanks,
> Rohit
So, I'm going to go ahead and ask WHY you want to do this?

If the purpose is just to "experiment with the ADF4350" there are 
relatively-cheap evaluation boards available for it.

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