Count (N): The total amount of the count (bar and window) as a pair among per rotation. 

 Cycle (C):  it indicates the fully one cycle of the electrical degrees measured as 360 °e degree. 

Cycle Error (ΔC): The deviation in the electrical degree among the pulse width against its ideal value. It's the  symbol of the uniform cycle.  

Pulse Width (P): Normally it refers to the "HIGH" number of electrical of the output during the one cycle.  

Pulse Width Error (ΔP): The deviation in the electrical degree among the pulse width against its ideal value about 180  °e degree. 

State Width (S): The number of electrical degree between Channel A and Channel B as a result of the transition  in the output state. There are 4 states per cycle from the output of Channel A and Channel B.  For each states nominated at 90 °e (S1-S4). 

State Width Error(ΔS):  The deviation in electrical degree among each of states width upon the ideal 90 °e.  

Phase (φ):  The number of electrical degrees between the centre of the high state on channel A and the  centre of the high state on channel B. This value is nominally 90 °e (the signals A and B can be  used for quadrature  

Phase Error (Δφ):  The deviation in electrical degrees of the phase from its ideal value of 90 °e.