Re: [Discuss-gnuradio] USRP MIMO node bandwidth

[Óscar González Fernández]

It is my fault, I have read my first question and I have realised it isn't well written.

Summarizing, the question is:

Do you think it can be possible to replace the CIC interpolation filters by a better ones in spite of losing variable interpolation rate capabilities? The only requirement is keeping the two TX and RX chains (and fitting into the FPGA). What is the current FPGA resources usage? and the expected after modifications?

P.S:
For our purpose, even de DDC in the FPGA can be supressed.

Óscar

El 19 de enero de 2010 20:58, Eric Blossom <address@hidden> escribió:

On Tue, Jan 19, 2010 at 11:19:04AM +0100, Óscar González Fernández wrote:
> The effect we observe doesn't seem to be a non linear effect due to high
> signal amplitude. Lowering the amplitude doesn't solve the problem. For
> example, when we transmit a 1 MHz tone we can see that a spurious tone
> appears at -3 MHz (referred to the carrier frequency) when using an
> interpolation rate of 16 (4x at the AD9862 and 4x at the FPGA). So, that
> spurious seems to be aliasing. Can you corroborate this?
>
> Óscar

Sorry, as Matt pointed out to me off-line, I wasn't answering the
question that you asked.

Eric