Incremental encoders generally have two outputs, called A and B, respectively. The two outputs are quadrature outputs with a phase difference of 90 degrees. The single-turn pulse number (PPR) of the incremental encoder is the number of square waves that will be output when it rotates one revolution. For example, if PPR is 600, it means that both A and B will output 600 square waves during one revolution, but the sequence is different. Optical (photoelectric) incremental encoders can have higher pulse counts per revolution, eg 2500 to 10000.
