| 摘要 |
Described herein are systems and methods for improving performance of single-frequency (single-point, single-bin) discrete Fourier transform (DFT) detectors by elimination of systematic errors from the detector output. Calibration procedures known in the art for practical implementations of such detectors do not provide adequate reduction of these systematic errors thus reducing utilization of these detectors in useful applications and products. The described methods, systems and devices allow such detectors to measure both DC and AC signals and, in latter case, considerably expand the operation frequency range without any additional hardware. These methods enable wide practical applications of DFT detectors across diverse variety of fields: from monitoring health of mechanical structures and fluid properties to impedimetric measurements in electrochemistry, monitoring of corrosion and bioimpedance. |
| 主权项 |
1. A method for measuring DC signals utilizing the DFT detector comprising of the following steps:
a. Using expressions (1) calculating the frequency range at which the in-phase output of a given DFT detector has a substantial gain factor for DC leakage, b. Choosing a frequency value form the frequency range calculated in step a. and for that frequency calculating the gain factor using expressions (1), c. Disconnecting the input of the DFT detector from any external circuits, d. Initiating and performing measurement at the frequency chosen in step b., e. Storing the in-phase output value of the DFT detector, f. Connecting the DFT detector input to the source of the DC signal of interest, g. Initiating and performing measurement at the frequency found in step a., h. Subtracting the value stored in step e. from the DFT detector in-phase output, i. The resulting value is measured level of the DC signal of interest with the gain factor determined in step b. |
