AMT absolute capacitive encoders consist of three basic parts as shown in the illustration above. The transmitter PCB emits an AC field that is distorted by the metal pattern on the rotor as it turns. A sinusoidal metal pattern on the rotor distorts the AC field in a way that is repeatable and predictable. This occurs as a result of varying capacitive reactance between the signal generated by the transmitter and the metal on the rotor. The field receiver uses the AMT ASIC to convert the modulated signal into digital position information, while the processor on the absolute encoder retrieves the position data from the ASIC and prepares it for export on the digital serial bus.