Common clock for two RFX2400 DB's

GNU Radio
1

Hello!
We consider using USRP with two RFX2400 dautherboards to build MIMO
system.
As I can see, each RFX2400 has Tx and Rx VCOs. Is it possible to use
common clock for these two dautherboards? (Frequency mismatch between
VCOs may prevent MIMO).

Thanks in advance.

2

Andrey A wrote:

Hello!
We consider using USRP with two RFX2400 dautherboards to build MIMO system.
As I can see, each RFX2400 has Tx and Rx VCOs. Is it possible to use
common clock for these two dautherboards? (Frequency mismatch between
VCOs may prevent MIMO).

All the VCOs are locked to the same reference, so you can do MIMO.

Matt

3

Andrey A wrote:

Hello!
We consider using USRP with two RFX2400 dautherboards to build MIMO system.
As I can see, each RFX2400 has Tx and Rx VCOs. Is it possible to use
common clock for these two dautherboards? (Frequency mismatch between
VCOs may prevent MIMO).

All the VCOs are locked to the same reference, so you can do MIMO.

Thank you, Matt.
One more question. What is the reference instability?

4

Andrey A wrote:

All the VCOs are locked to the same reference, so you can do MIMO.

Thank you, Matt.
One more question. What is the reference instability?

Are you looking for the frequency accuracy? phase noise? I’m not sure
what you mean.

Matt

5

All the VCOs are locked to the same reference, so you can do MIMO.

Thank you, Matt.
One more question. What is the reference instability?

Are you looking for the frequency accuracy? phase noise? I’m not sure
what you mean.

We are concerned about frequency accuracy.

6

We are concerned about frequency accuracy.

The clock has a 20 ppm specification, but at room temperature is
typically within 5 ppm.

Matt

7

We are concerned about frequency accuracy.

The clock has a 20 ppm specification, but at room temperature is
typically within 5 ppm.

We need 10^(-9) frequency accuracy. Is there any way to approach to this
accuracy?

Thank you.

8

Andrey A wrote:

this accuracy?
Why do you need such high accuracy?

If you really do, which I don’t think so, you can use an external clock.

Matt