[eagle] Re: Eagle Microwave Antenna Arrays-- mechanical concepts
John B. Stephensen
kd6ozh at comcast.net
Sun Mar 25 16:06:47 PST 2007
The big current spike is during start up and the static current afterwards
is low enough so that you can manage power dissiation. 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.
----- Original Message -----
From: "Matt Ettus" <matt at ettus.com>
To: "AMSAT Eagle" <Eagle at amsat.org>
Sent: Sunday, March 25, 2007 21:40 UTC
Subject: [eagle] Re: Eagle Microwave Antenna Arrays-- mechanical concepts
> John B. Stephensen wrote:
>> The amount of power required by the FPGA depends on the number of
>> logic elements used and the speed of operation. Anything that isn't
>> clocked in the FPGA consumes almost no power so the thermal
>> dissipation is controlled by the logic designer.
> This is not true anymore. Small geometry devices (< 90nm) can consume a
> lot of static power.
>> DCMs require a lot
>> less power than an external DDS and an FPGA would be a good place to
>> put other logic.
> DCMs have horrible phase noise. You wouldn't want to use them for
> generating clocks for ADCs, DACs, LOs, or PLLs.
> Via the Eagle mailing list courtesy of AMSAT-NA
> Eagle at amsat.org
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