good clocks (not using GPS) and multi-channel hw [was: sidebands of great justice]

[Andy Isaacson]

On Thu, Nov 07, 2013 at 11:57:25PM -0800, coderman wrote:
> On Thu, Nov 7, 2013 at 11:32 PM, coderman <coderman at gmail.com> wrote:
> > ...
> > SDR MIMO kit leaves much to be desired, however.
> 
> let me clarify:
> 
> the hardware available for SDR MIMO development leaves much to be desired.
>   ... the blocks and implementations for OFDM coding in software are OK :)
> 
> USRP N2X0 can do it, other setups require external reference clock
> with high fidelity.  any recommendations for non-GPS clocks performing
> at 50-100ppb or better?

You don't need a global clock like GPS for MIMO, just a local high
quality clock pulse to build a time base across multiple transceivers.

... unless I'm missing something?

Nuand already has 2x2 MIMO by slaving one board to another's clock, and
is developing a 4x4 MIMO clock distribution board.

-andy