[time-nuts] Fwd: sysclock source for AD9912 DDS?

[Gerald Molenkamp]

Look up PA3AKE, he built a 1 GHz source clock, Martein also provides a substantial amount of research data.

Good luck for the new year.

Gerald

VK3GJM

Sent while out and about

Begin forwarded message:

From: Anders Wallin <anders.e.e.wallin at gmail.com<mailto:anders.e.e.wallin at gmail.com>>
Date: 31 December 2013 2:56:03 AEDT
To: Discussion of precise time and frequency measurement <time-nuts at febo.com<mailto:time-nuts at febo.com>>
Subject: [time-nuts] sysclock source for AD9912 DDS?
Reply-To: Discussion of precise time and frequency measurement <time-nuts at febo.com<mailto:time-nuts at febo.com>>

I've tested the AD9912 evaluation board:
http://www.anderswallin.net/wp-content/uploads/2013/12/dds_test_2013-12-30.png

I want to use it with a 10MHz external input clock, but it looks like the
on-board PLL that generates a 1200MHz sample clock from my input isn't that
great, since I get strong side-bands on the output that are only 18-20 dB
down from the fundamental.

So it looks like I need to supply a clean 800-1000MHz clock to the DDS to
get a clean output. Any ideas/suggestions for generating this from a 10 MHz
sine?
Driving the DDS system clock from an expensive RF generator (e.g. HP 8648A)
would be possible but I'd prefer a PLL from 10MHz if it's doable
simply/cheaply.

Anders
_______________________________________________
time-nuts mailing list -- time-nuts at febo.com<mailto:time-nuts at febo.com>
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
--
Message  protected by MailGuard: e-mail anti-virus, anti-spam and content filtering.http://www.mailguard.com.au/mg