A method for signal processing of flame detection system for thermal energy equipment is presented. An AVR microcontroller unit（ MCU） used as core chip

the multistage amplifiers combined with multiple ADC channels in signal amplification circuits are adopted to implement adaptive gain modulation and expand dynamic range of input. Statistical average of the input signals represents the flame signal intensity

and the flame signal frequency is analyzed and calculated by fast Fourier transform（ FFT）. During FFT calculation process

use fixpoint calculation and table lood-up method to simplify the calculation procedure

reduce resource consumption and improve arithmetic speed

fixed-point FFT of 512 samples is achieved within 300 ms with 1Hz frequency resolution

guarantee real-time

precision and reliability of flame signal detection.