AC voltage measurement with digital sampling

AC voltage measurement is the base of AC electric quantity measurement. Digital sampling measurement system is developed. In which the AC signal under test is transmitted into the input of A/D converter by voltage follower, and under the control of MCU, A/D converter synchronous sampling by full period, and sampling data is calculated by computer into which transmitted by optocoupler. Consistency of sampling measurement compared with Fluke 5790A is within 2 × 10-5 generally. It is found that the main contribution of uncertainty in the system is the integral nonlinearity (INL) of A/D converter, and the influence of quantization error and timing jitter can be decreased by increasing the sampling frequency.