MIMO and External Reference

GNU Radio
1

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?

Thanks.

Joe

2

On 08/01/2011 01:50 PM, Joe Farkas wrote:

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