Chapter 5Signals and Noise

Modulation – Converting a dc signal to a higher frequency

• 1/f noise is less troublesome at higher frequencies

Choppers

Lock-in amplifier

After 9 repeatmeasurements

S/N increased by 3

Signal Averaging

Click graph

Moving average

Polynomial Smoothing

B: quadratic 5 pt smooth

A: raw data

C: 4th degree 13 pt smooth

D: 10th degree 77 pt smooth

Polynomial Smoothing

Click graph