Analysis And Research Of Quantization Error In Digital Measurement And Processing

Without measurement,there is no science,and precision measurement is the core force driving the progress of science and technology.With the rapid development of semiconductor technology and digital signal processing technology,digital measuring and processing technology with the advantages of high precision,high resolution and fast response to replace traditional analog measuring way become the mainstream trend of modern measurement.It has been widely used in navigation and position,aerospace,power electronic,network communications,industrial manufacturing and other fields.However,the problem of quantization error becomes a restrict bottleneck to the further development of digital measuring and processing technology,how to effectively inhibit the quantization error is the hot issue in the field of measurement and control.In traditional digital measuring and processing,it is mainly relied on raising the ADC conversion digit to suppress the quantization error,but this is the cost of conversion rate,which cannot satisfy the requirements of the current digital measurement.In this paper,the measurement of digital periodic signal is taken as the main research object.In the process of digital periodic signal measurement and processing,it is found that in addition to the A/D quantization error,there is also a quantization phase transition phenomenon associated with the frequency relation between the measured signal and the sampling clock signal.The quantization phase transition is a subdivision of the higher resolution of the periodic signal phase.The mechanism,existence form and interrelation of the two quantization errors can be analyzed to determine the key factors affecting the resolution of digital measurement.Combined with the clock cursor effect and border effect can be targeted to suppress quantization error and frequency measurement as the breakthrough point to illustrates the feasibility of the quantization error suppression.Clock cursor effect studies the frequency relationship between the measured signal and the sampling clock signal,so that the quantitative process of the measured signal presents a continuous and orderly cursor phenomenon,and realizes the dense sampling compared to the ADC sampling rate,thus restraining the quantization error caused by ADC.Border effect studies the border characteristics of the quantized fuzzy area of ADC.Compared with other positions,the border position has higher stability and is more sensitive to the change of the measured signal.It can greatly reduce the influence of quantization error and make the measurement accuracy much higher than the resolution itself.Through the application of the direct digital precision phase difference measurement system,it is proved that the accuracy of digital measurement and processing based on clock cursor effect and border effect can be increased by one to three orders of magnitude compared with the traditional digital measurement,and the unification of measuring accuracy and ADC conversion rate,which provides a new direction for the development of the digital measurement.The unique advantages of periodic signal phase measurement and exploration are of great significance to the development of China’s navigation,positioning and timing.