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Re: [Discuss-gnuradio] FPGA Questions
From: |
Eric Blossom |
Subject: |
Re: [Discuss-gnuradio] FPGA Questions |
Date: |
Sat, 24 Feb 2007 18:02:41 -0800 |
User-agent: |
Mutt/1.5.9i |
On Sat, Feb 24, 2007 at 05:13:22PM -0500, Brian Padalino wrote:
> On 2/24/07, Thibaud Hottelier <address@hidden> wrote:
> >Hi all,
> >
> >I have dived into the fpga code and I have now much clearer picture of
> >what is going on, but also much more questions :)
> >
> >The Tx CORDIC is disabled in the code I checked out. Why?
>
> I could be wrong, but I think the TX CORDIC is disabled due to the
> fact that the samples being delivered over USB are already complex.
> Any other frequency translation is done within the AD9862 transmit
> path.
>
> Anyone can feel free to correct me if I am wrong.
You are correct ;)
> >I have failed to find a description of how to control the AD9862 chip on
> >the Analog Device web site. Where is this documented?
>
> http://www.analog.com/UploadedFiles/Data_Sheets/AD9860_9862.pdf
> >I would like to be able to choose the power level and the channel used
> >to transmit every packets. To choose the channel, is it possible to
> >tweak the CIC Decimating filter to slightly alter the signal frequency
> >or is it a better idea to do it in the AD9862?
The CIC interpolator doesn't perform freq translation.
If you want to change the channel, you'll want to issue the equivalent
of a "tune" command (probably several sub-operations inband)
immediately prior to sending the samples for the packet.
Yes, I know you're waiting for me to flush out the packet format.
Eric