Fig. 2: Lock-in amplifier operation for a channel.
From: Flexible eddy current array measurement system for crack detection in weld zones of steel structures

a Block diagram of Lock-in amplifier. b LabVIEW-based Lock-in amplifier program.
From: Flexible eddy current array measurement system for crack detection in weld zones of steel structures
a Block diagram of Lock-in amplifier. b LabVIEW-based Lock-in amplifier program.