Fixed-point implementation of active disturbance rejection control for superconducting radio frequency cavities

A fixed-point implementation of the previously explored active disturbance rejection control (ADRC) for superconducting radio frequency (SRF) cavities is presented in this paper. The developed fixed-point algorithm is very suitable for being implemented on a field programmable gate array (FPGA) allowing high sampling rate (>20 MHz), which may be needed in special applications. The design tradeoffs are discussed as well to ensure its implementation on a low end FPGA with limited resources. Through both simulations and hardware tests, it is demonstrated that the fixed-point algorithm provides performance as good as the floating-point algorithm.