In this group we will discuss the use of Direct Digital Synthesis (DDS) in amateur radio VFO applications. In particular, we will discuss the IQ-VFO and IQPro project (pictured on the right) designed by Craig, AA0ZZ, which uses an Analog Devices AD9854 DDS and is controlled by PIC microcontrollers. As implemented in the IQ-VFO/IQPro, with a 125 MHz clock oscillator, the AD9854 provides two outputs (In-phase and Quadrature) with a frquency range of 0 to 30 MHz. The dual outputs make it ideal for simple or advanced amateur radio transmitters, receivers, or transceivers. For example, it is a nice match for the R2Pro direct-conversion receiver designed by Rick Campbell, KK7B. For more information on how I and Q are used in the modulation and demodulation of signals, look in your reference books regarding phasing.

For information about availability see my web page, www.cbjohn.com/aa0zz

The membership of the group is restricted to keep out spammers. Feel free to join us, even if you just want to browse.

-Craig, AA0ZZ