An FPGA implementation of the Goertzel algorithm in a Non-Destructive Eddy current Testing

The paper presents an implementation of the Goertzel algorithm in FPGA (Field Programmable Gate Array) logic as a proposed algorithm utilized in Eddy current NDT (Non-Destructive Testing) instrumentation equipment. The FPGA running a real-time Goertzel algorithm in Eddy current NDT application is a novel approach different from the usual methods; such are the quadrature demodulation and discrete FFT. The paper provides a brief overview of the Eddy current instrument hardware and gives a mathematical background on Eddy current signals. It also shows a real-time implementation of Goertzel algorithm in SoC (system-on-chip; FPGA/ARM based chip) and provides experimental results obtained by using common EC NDT probes. The results are compared to the results of several commercial Eddy current instruments.