[eagle] Re: Eagle Microwave Antenna Arrays-- mechanical concepts

Matt Ettus matt at ettus.com
Mon Mar 26 15:07:31 PST 2007


John B. Stephensen wrote:
>  The big current spike is during start up and the static current
>  afterwards is low enough so that you can manage power dissiation.

Simply not true.  Large 65nm FPGAs dissipate several watts of standby power.

>  I
>  wouldn't use DCMs for the reciver as it must deal with multiple
>  narrow-bandwidth signals. The downlink will be about 2 Mbaud BPSK so
>  phase noise isn't a big issue in generating low-frequency signals to
>  be upconverted.

I can speak from experience here.  Clocks coming out of the FPGA are 
simply not clean enough to use for this purpose.

Matt


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