Re: [Discuss-gnuradio] ADC calibration

[Matt Ettus]

On 07/30/2010 11:32 AM, Daniel Halperin wrote:
> Hi,
>
> I'm calibrating my USRP setup using a function generator. I remember
> seeing that someone else had done this before in the past and written
> down a bunch of (input voltage, ADC output) pairs on the web somewhere,
> but I'm unable to find it on the wiki even with google site: search.
>
> Does anyone have a pointer?


When using a BasicRX or LFRX with the PGA set at 0dB gain (USRP1 only), 
+10dBm is full scale on the ADC.  On the USRP2 full scale on the ADC is 
full scale when it gets back into gnu radio.  On the USRP1 full scale on 
the ADC is (1.67/2) times full scale due to the gain of the CORDIC.

+10dBm = 2Vpp = 1 Vpeak = 0.7 Vrms

With other daughterboards you will need to calibrate at the frequency of 
interest.
Matt