[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Discuss-gnuradio] ADC calibration
From: |
Daniel Halperin |
Subject: |
Re: [Discuss-gnuradio] ADC calibration |
Date: |
Fri, 13 Aug 2010 12:17:27 -0700 (PDT) |
On Tue, 10 Aug 2010, Matt Ettus wrote:
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.
Thanks, that's helpful. However, I can't quite make the math work:
P = V^2/R ; 0.01 W = (1 V)^2/R ; R = 100 Ohms.
But we're using SMA connectors which are 50 Ohms right? Or should I be
putting 1 Vpeak I *and* 1 Vpeak Q and getting the 100 Ohms from the
combination of the two 50 Ohm connectors?
Thanks,
Dan
(forgot to reply all first, sorry for the double-msg Matt)