Low latency demodulation for Atomic Force Microscopes, Part I efficient real-time integration

Abstract

This paper describes methods for doing high speed, low latency, coherent demodulation of signals for dynamic or AC mode in Atomic Force Microscopes (AFMs) [1]. These demodulation methods allow the system to extract signal information in as little as one cycle of the fundamental oscillation frequency. By having so little latency, the demodulator minimizes the time delay in the servo loop for an AC mode AFM. This in turn minimizes the negative phase effects of the demodulation allowing for higher speed scanning. This part of the paper describes the mixing and integration portion of the demodulator. Part II [2] describes efficient methods for extracting magnitude and phase in real time.