Measuring methods are determined by the measuring principle and the measuring method and are realized in pointer instruments or digital measuring instruments. While the measuring principle forms the physical basis for the measurement, the measuring method is concerned with the execution of the measurement.
Measurement methods can be classified into direct and indirect, as well as analog and digital measurement methods. In analog measuring methods, the measured variable is continuously displayed on a scale display. The measured value can change over time and is read as a numerical value on the scale display under the pointer. Other measuring instruments with screen display such as oscilloscopes or spectrum analyzers show the continuous changes directly on the screen.
With digital measuring methods, the measured value is converted into a digital value in an A/D converter before it is displayed on the numerical display. The digit display is not in real time, its continuum depends on the sampling rate of the AD conversion. The higher this is, the more distinguishable signal fluctuations become.