Improved Dual Measurement System based on SDFT-FLL with High Accuracy

In this paper, a digital resistance and capacitance (RC) measurement technique has been presented. The proposed RC measurement technique is based on RC-to-frequency conversion. Sliding discrete Fourier transform (SDFT)-based frequency-locked loop (FLL) is designed to estimate the frequency of the square wave signal. Resistance within the range of 108 - $392 \mathrm{k}\Omega $ while capacitance within the range of 300 - 900 pF has been tested and verified through this technique. The proposed method is also compared with the existing techniques and also with commercially available LCR meters. The average value of resistive and capacitive measurement accuracy obtained is 0.1012%. Within the tested range, the reported accuracy is quite comparable with the existing techniques as well as with the commercially available handheld LCR meters.