Prefilter Design Method for Weak Signal Detection with LIA
Houjun Wang · Measurement & Control Technology · 2007
A method to bate noise of preamp is discussed.The primary noise generation part of system is analyzed.A prefilter made up by inductive parts is added ahead of preamp.That can efficiently reduce the noise.A method to design prefilter is developed and proved optimal.Applying this method,a better performance(7.25% improved) is gained on the circuit for weak signal detection basing on lock-in amplifier(LIA).It is a very important to improve signal to noise ratio(SNR) for weak signal detection.