A Digital Lock-in Amplifier Based on Adaptive Kalman Filter for Rail Defect Detection

Table 1

Parameters of four cases for demodulation.

Parameters	Case 1	Case 2	Case 3	Case 4
A0	0.1 V	0.1 V	0.1 V	0.1 V
θo	Constant	Constant	Constant	Constant
A1	0 V	0 V	0.01 V	1 V
A2	0 V	0 V	0 V	1 V
VDC	0 V	0 V	0 V	1 V
SNR	100 dB	100 dB	100 dB	−1 dB