Quadra: High-Voltage RF Waveform Generator
April 2026
A software-defined high-voltage RF generator that drives 3 kVpp sinusoids into 1 nF capacitive loads from DC to 10 MHz, built for the quadrupole ion guides of a custom charge detection mass spectrometer in the Williams lab at Berkeley. The signal chain has three stages: a host-controlled DDS arbitrary waveform synthesizer, a power amplifier, and a custom-wound 1:12 center-tapped step-up transformer that produces two 180-degree out-of-phase outputs to drive opposing rods of the quadrupole. The host interface speaks over SPI and runs on both Windows and Linux through a custom serial driver layer. I worked on the synthesis and amplifier PCB and validated the full chain in SPICE before bringup, paying particular attention to transformer parasitics and amplifier stability into the capacitive load. I also coiled custom transformers and validated their performance on the bench. Team: Engineering Solutions @ Berkeley