A Sub-Hertz-Resolution RF/DC Driver Platform for Quadrupole Mass Filtering Processes: Coupled Modeling, Hardware Design, and Benchtop Characterization

In quadrupole mass filtering processes, ion trajectory stability is governed by the Mathieu parameters (a,q), which scale inversely with the square of the excitation frequency (ω−2). High-quality-factor (Q≥100) series resonant networks are widely employed for passive radio-frequency (RF) voltage step-up. However, their narrow passbands render the output amplitude vulnerable to temperature-induced capacitive detuning. Furthermore, conventional microcontroller-based Direct Digital Synthesis (DDS) architectures rely on integer register parsing, constraining the tuning resolution to ≥1 Hz and introducing quantization errors during frequency scanning and tracking. This paper presents the coupled modeling, hardware design, and benchtop characterization of a software-defined RF/DC driver platform with 0.1 Hz frequency resolution for resonant quadrupole mass filters. Numerical modeling coupling fourth-order Runge–Kutta (RK4) ion dynamics with RLC transfer functions demonstrates that a 0.1 Hz frequency increment restricts stability parameter shifts to Δq/q<2×10−7, limits detuning voltage attenuation to ΔV/V0<10−5, and eliminates peak apex truncation at mass resolving powers R>1200. The hardware platform integrates an STM32 microcontroller, an AD9954 DDS core (400 MSPS), an IEEE-754 32-bit floating-point Ethernet communication pipeline, a 16-bit bipolar DC bias stage (0.1 mV step resolution), and an in-loop baseband telemetry channel. Benchtop measurements demonstrate continuous RF generation from 10 Hz to 10 MHz with a relative frequency error below 0.070%. On a 1.0 MHz series resonant network loaded with a 50 pF equivalent capacitance, thermal measurements reveal an open-loop start-up frequency scatter of 0.266% (2.66 kHz), demonstrating the necessity of sub-Hertz frequency correction to restore resonance. The telemetry channel achieves an acquisition stability relative standard deviation (RSD) of 1.2×10−5 via a 500-sample moving-average filter, enabling closed-loop frequency tracking to maintain the normalized RF amplitude within 99.55% to 100.00% across a 60-min thermal cycle. Characterized on a benchtop equivalent load, this hardware platform provides a deterministic electronic foundation for dynamic resonance re-centering and stable ion transmission in high-Q quadrupole systems.