Date: Mon, 22 Feb 1999 11:44:16 -0500
From: "'Geri' Kinzel, DK8KW" <DK8KW@compuserve.com>
Subject: LF: Re: Re LF Xtal/mixer Exciters/Synthesizer (Repost)
To: rsgb_lf_group@blacksheep.org
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>Dear Geri,

>Care to share with us the source of the kit?

>73's ................. Zim ............ VK3GJZ

No, Zim, I don't mind at all! Thats what I try since several days! I will
try again:


The synthesizer I am using is either available as a kit (see below) or as a
build and assembled unit. It makes use of an integrated DDS circuit named
AD9850.  

There are a couple of information sources available for the AD9850. 

The Analog Devices AD9850 is a CMOS, 125 MHz complete direct digital 
synthesiser on a single chip. It uses a single 5 V or 3.3 V supply, and
with a 125 MHz clock, can generate a low-distortion sine wave or a square
wave, from under 1 Hz up to about 60 MHz, with a tuning resolution of
0.0291 Hz. Full data on the device is available from ADI's web site:

                                        http://www.analog.com

Off course, this device was never created for low-frequency, however, I got
hold of a kit that includes a controller and a display, it has one Hertz
resolution and ten memory channels and so it is ideal to drive a 
longwave-PA. It even has a build in correction factor for frequency
stability, so once you found out how many ppm you are away from the qrg
where the device should be, you can program that permanently into the
memory. This allows a freqency stability and repeatability of around 1 Hz