Re: [Discuss-gnuradio] MIMO and External Reference

[Josh Blum]

On 08/01/2011 01:50 PM, Joe Farkas wrote:
> Hi,
> 
> I am using a couple N210s with the latest firmware/software. I am
> using the MIMO cables to time align and synchronize two transmitters
> and am decoding them on a separate board (non USRP). I would also like
> to synchronize my receiver to my transmitters by using an external
> reference to avoid baud compression.
> 
> I am currently using GRC, where I have a couple data streams into a
> USRP Sink block configured for multiple channels. If I configure the
> reference signal to be the MIMO cable, I believe it uses the internal
> clock. If I configure the reference signal to be external, I believe
> it will synchronize everything, but they won't be time aligned. Is
> there a way to both time align and synchronize via an external signal?
> 

Make sure you have the latest GRC, I added per-board reference
configuration settings.

Set one of the mboards to MIMO cable, and set the other to the reference
of your choosing (internal, or external if you provided).

The alignment of samples is automatic if the block has multiple ports.

-josh