Nice article on making an Arduino DDS…

December 23, 2011 | Amateur Radio | By: Mark VandeWettering

My experiments with generating RTTY signals yesterday made me begin to think about generating RTTY signals with an Atmel/Arduino setup. The obvious way is to use PWM and a low pass filter to approximate a sine wave. While doing a bit of research, I found the following link which seemed to be nearly ideal: it even included an amateur radio application that uses an Arduino to generate the tones necessary to transmit WSPR. It also has a very nice lowpass filter design that can be pressed into service to smooth the PWM output. Stashed for future reference:

Arduino DDS, with WSPR applications

Comments

Comment from Ricardo – CT2GQV
Time 12/23/2011 at 9:53 am

Can’t the “gameduino” generate also the signals? Just thinking, have no experience with it.

Comment from Mark VandeWettering
Time 12/23/2011 at 11:38 pm

Yeah, it can, but it’s like killing flies with a cannon: at around $50, adding one to a build isn’t all that economical unless you are using more of its capabilities. I’m debating using PWM/DDS (the cost of which is in increased complexity and the inductors in the necessary low pass filter) versus something like the XR2206 (a dedicated frequency generator, which costs around $5 but simplifies the software considerably).