Building A DDS Module Using AD9835

The small size and simple handling of AD9835 makes it easier to design a DDS module in order to do various digital RF modes with a PIC microcontroller.

During the construction, a 50MHz oscillator module was packed with the AD9835 since it comes in a very small TSSOP housing. This move is necessary in order to handle the form of the AD9835 and to start developing. Also included are some parts needed for proper operation on a small PCB with two connectors with standard pin sizes. This will enormously simplify the development while using a breadboard for designing systems with the AD9835.

Based on this module and a simple PIC16F84, a code sample of a SSTV Test Generator can be found which will show that even uncommon digital modes can be done with a PIC. A color bar screen is produced by the Test Generator using SSTV protocol.

A single sided PCB is used with the exception of the 50MHz oscillator module and the coil which a normal size. All the other components are of SMD size 1206. Since the AD9835 comes in TSSOP housing, special care must be taken during soldering.

Rest of the project