Having the need for a configurable reference frequency source i decided to use some of the AD9832 flying around here to build up a small
DDS signal generator. The work done by SM2LKM, Johan was a excellent point to start.
Find his documentation here: http://home.swipnet.se/~w-41522/minidds/minidds.html
I decided to create my own board to fulfill some requirements
regarding connectors and formfactor of the board. From the schematic point it is almost the same than that from Johan except the low pass filter i used and
the additional divider for the reference oscillator.
The board does not contain any microcontroller. So you can decide whether you want to connect it to a PC or to a microcontroller. I created a small piece of C-code software for Atmel AVR microcontrollers (Atmega644, but you can adapt it to different one) to control and test the signal generator. At the moment it is just possible to enter the desired output frequency and the divider is set automatically. It does not make any use of the second frequency register and the phase registers. In addition i did some experiments in creating a WSPR signal with this setup.
Some more information you can find in this document (2.5MByte) :
The complete sources including layout, documentation sources and software sources can be found here (12MByte) :
Would be nice to hear from you if you are interested in this work.
73´s de Mario