Build an 8 GHz Sampling Oscilloscope with Analog Devices’ ADCMP582 Comparator

Oscilloscopes, you don’t always need one, but when you do the good ones can cost quite a bit. There is hope. Instead of buying an expensive piece of equipment, others such as programmer Ted Yapo, decide to create their own, which he has done with his open source 8GHz Sampling Oscilloscope.

Yapo's project is a basic multi-GHz sampling oscilloscope for people on a budget and is still a work in progress. It offers bandwidths in the 7-8 GHz range with >= 100 GSa/s equivalent-time sampling, and around 500 k comparisons per second in real-time. Those numbers are achieved using an Analog Device ADCMP582 comparator, which is built on SiGe and has a sampling aperture of 5 ps, and a typical front-end bandwidth of 8GHz. Yapo's oscillator also packs incredibly fast 74AUCxx gates (fed by a 12V DAC), which allows it to start up quickly after the gate input transitions, and oscillates at around 360MHz.

The Sampling Oscilloscope has an input range of +/- 2V, a vertical resolution of 1mV, a rise time of 48 ps (10%-90%), and an effective bandwidth of 7GHz. It also features an ET sample rate of 100 GS/s, a TDR resolution of 5mm (FR4), and costs roughly $100 to build for the current Prototype 2 version. An impressive price for what it can do.

Yapo is currently looking to add some improvements to his design, including incorporating a 32-bit CPU, integrated power supply, and time-based enhancements. A complete walkthrough of Yapo's open source 8GHz Sampling Oscilloscope on his project page, which he admits is outdated and suggests watching the video posted above for the latest revisions.