[The realization of moving mirror scanning in FTIR spectrometer using completely digital control method]

Area of Science:

• Optics and Photonics
• Control Systems Engineering
• Signal Processing

Context:

• Conventional scanning mirror control often uses complex digital-analog hybrid designs.
• This complexity can hinder efficiency and precision in optical systems.
• There is a need for simplified and effective control methodologies.

Purpose:

• To develop a concise and efficient control method for scanning mirrors using entirely digital signals.
• To replace complex hybrid designs with a purely digital approach.
• To enhance the performance of spectral analysis systems.

Summary:

• A novel control algorithm is implemented within a Complex Programmable Logic Device (CPLD).
• The algorithm processes quadrature encoder pulses (A and B) for precise position and velocity control.
• The CPLD generates Pulse Width Modulation (PWM) signals, which are then used to drive a voice coil motor for mirror actuation.

Impact:

• Achieved velocity stability for the moving mirror exceeding 97.2%.
• Significantly improved the signal-to-noise ratio (SNR) of measured spectra.
• Guaranteed enhanced accuracy in both qualitative and quantitative spectral analyses.