How to distinguish the number of lines of the photoelectric encoder？

Encoders are divided into two categories: incremental and absolute. Their so-called line numbers all indicate their resolution (resolution). The resolution of an incremental encoder is expressed by the number of pulses output per revolution, ppr (pulse per revolotion) such as 2000 ppr, 8192ppr The resolution of an absolute encoder is expressed in bits, bit (binary digits). Such as 17bit, 20bit