A Fast Temperature Compensation Method for Digital Oscilloscope Amplitude Calibration

With the rapid development of modern science and technology, the demand for accurate observation of complex signals is increasing vastly, which makes the digital oscilloscope develops towards a higher sampling rate and resolution. However, the amplitude measurement accuracy of the digital oscilloscope is not only affected by the realization circuit complexity but also by a variety of unstable factors such as temperature in the environment. Therefore, a lot of complex amplitude calibration processes are needed before practical use, and the calibration accuracy is also difficult to reach a stable level. This paper presents a fast temperature compensation method based on quadratic curve fitting for digital oscilloscope amplitude calibration. First, an automatic amplitude calibration system is set up with an oscilloscope to be calibrated, a calibrator and a temperature-humidity test chamber. Then an automatic data recording and processing method based on quadratic curve fitting is proposed, and the specific expressions are given for the calibration process. Finally, the automatic amplitude calibration is realized and verified in the digital oscilloscope with 8GHz bandwidth and 2mV/div∼1V/div vertical sensitivity. The test results show that the proposed method can automatically calibrate the amplitude accuracy of 0.5%FS at 0°C∼40°C, and the whole process only needs two temperature cycles. This greatly improves the efficiency of amplitude temperature calibration, reduces tedious human work, and provides greater convenience for the accurate measurement of digital oscilloscopes.