Does Analog Devices offer a list of manufacturers of oscillators for DDS devices?

We do not recommend a specific manufacturer, but Ecliptek, Epson, Vari-L, Connor-Winfield, Wenzel, and Valpey-Fisher are known as sources for high quality parts.

My evaluation board is not working; the software is reporting a USB Communication Error. I verified that the evaluation board is connected to the PC and powered. What else can I check?

USB communication errors can be due to a missing or incorrect USB driver. This can occur if the evaluation board is connected to the PC before the evaluation software is installed. It can also occur if the user responded "STOP Installation" to the warning that the driver "has not passed Windows Logo testing."

How to fix: Disconnect the evaluation board from the PC, and verify that the evaluation software is installed. Right click on "My Computer," select "Properties," "Hardware," then "Device Manager." In "Device Manager" double click on "Universal Serial Bus Controller," for a list of USB devices connected to the PC. Now connect the evaluation board to the PC. The list of USB devices in Device Manger will update and a new item "USB Device" should appear. Right click on the new "USB Device" in the list and select "Update Driver." The Hardware Wizard should start, then select "Install the software automatically." The wizard should start the Evaluation Board installation, and a warning will appear that the software "has not passed Windows Logo testing to verify its compatibility with Windows XP." Click "Continue Anyway" to finish the installation. Now start the evaluation software, a message "Firmware Downloaded" should appear and the evaluation software should work properly.

Where can I find some good background material on direct digital synthesis?

The following DDS tutorials should be helpful: A Technical Tutorial on Digital Signal Synthesis and
Tutorial MT-085, Fundamentals of Direct Digital Synthesis