Advantages of single-field scanning

In this example, a glass scale was marked in order to simulate contamination. The encoder signals from the four-field scanning and single-field scanning are compared.

In the oscilloscope’s X/Y graph, the output signals appear as a Lissajous figure. Ideal output signals appear as a concentric inner circle. Deviations in the circular form and position are caused by position error within one signal period (see Measuring Accuracy) and therefore go directly into the result of measurement. The size of the circle corresponds with the amplitude of the output signal, and can vary within certain limits without influencing the measuring accuracy.

The image demonstrates the effects on the signal’s phase angle and offset.