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Re: [Discuss-gnuradio] TX characterisation of USRPN210 with SBX daughter
From: |
Martin Braun |
Subject: |
Re: [Discuss-gnuradio] TX characterisation of USRPN210 with SBX daughterboard |
Date: |
Tue, 25 Mar 2014 12:34:09 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 |
Ron,
thanks for the input!
On 03/25/2014 12:02 PM, Ron Economos wrote:
> I took a look at the SBX schematic. The final output
> uses a Mini-Circuits PHA-1+ MMIC amplifier that's
> rated at +22 dBm output power at 1 dB compression.
>
> It would seem that the gain distribution of the SBX
> is arranged so that the PHA-1+ cannot be overdriven,
> even at DAC full-scale and 0 dB attenuation. That is,
> you cannot saturate the SBX.
>
> So your measurements are showing that the SBX is
> quite linear over it's operating range.
>
> BTW, I'm not really familiar with the USRP (I'm a bladeRF
> user), but the amplitude value in tx_waveforms is most
> likely just a relative amplitude (with 1 equal to DAC
> full-scale), and not an actual voltage.
That is correct. If you were using GNU Radio, and connected that to a
USRP, this would be amplitude of the digital signal going into the USRP
sink.
Martin