I’m working on a USB DDS (direct digital synthesis) board that will be a plug-in module for another application. Here’s a block diagram:

It has a few interesting features that I thought others might be interested in:

– AD9852 direct digital synthesis IC with 300 MHz adder, 48 bit accumulator, and digital inverse sinc filter
– A fairly powerful microcontroller with full speed USB
– A low jitter clock synthesizer PLL: LMK03001C
– An MCP3553 22 bit A/D converter
– Gain block chip from Mini Circuits: GALI-74+
– 6 layer PCB construction for excellent ground and VDD planes

These features should give this board possibilities in amateur radio and perhaps homebrew instrumentation. Changing the filter components could allow usage from very low frequencies up to around 125 MHz.

Utilizing upper frequency images would give you usable range into 500 MHz or possibly a bit more depending on how good the RF layout is. The PCB is FR4 and uses standard 0603/0805 discrete parts, so it probably won’t give usable signals into the microwave region.

I’ll share more once I have the schematic done.