Hi Liang,
As you can notice in the datasheet (Chapter 8), the KMZ80 provides a digital output signal on pin OUT/DATA (if bit 12 in register SYS_SETTING is set to logic 1) compliant with the SAE J2716 SENT standard.
The measured angle α is converted linearly into a value, which is digital encoded in SENT frames. Either a positive or a negative angular slope characteristic is provided for this purpose.
Best regards,
Tomas