Re: [Discuss-gnuradio] OFDM results.

[Matt Ettus]

Bob McGwier wrote:
> The USRP is not in the same league with the USRP2.  The on board 
> oscillator is much better but external oscillators will make it even 
> better.  So the answer is a big yes, the USRP2 will be better.

Actually, I need to disagree again here :)

The master oscillator on the USRP1 is actually exceptionally clean.  It 
may be as much as 20ppm off in frequency and will drift with 
temperature, but it is very clean down to 10 Hz offsets.  It is amazing 
what you can do with a cheap oscillator as long as you don't make it 
tunable or temperature compensated.

As soon as you make an oscillator temperature compensated or voltage 
controlled, as we need to in the USRP2, you have to go to much greater 
lengths (and expense!) to get comparable phase noise performance.  So 
the USRP2 will have roughly the same phase noise performance as the 
USRP1.  The USRP2 will be lockable to an external oscillator, but that 
will only affect phase noise at less than 100 Hz offsets.

Matt