Interpolation

The output signals I₁ and I₂ normally correspond in their signal periods with the grating period of the encoder. To attain finer measuring steps for higher positioning accuracy and higher control quality, the sinusoidal encoder signals can be interpolated in interface electronics. This interpolator can be located in the encoder (e.g. in the scanning unit or the connector), in a separate Interface unit (e.g. IBV or EIB from HEIDENHAIN) or in the subsequent electronics (position display unit or CNC). Interpolations factors of up to 100-fold for position measurement and up to 4096-fold for velocity control are common.