Page 218 - Mechanical Engineers' Handbook (Volume 2)

4 Stability and Phase Analysis 207

Figure 11 Use of bandpass filter for discriminating signal from noise.

H imag
arg H(j ) ∠H real + jH imag tan 1
H real
The arctan will produce the principal value of the phase shift, not necessarily the cumulative
phase shift, since the arctan function produces principal value tan ( ) .Itis
1
possible to recover the accumulated phase shift by factoring the rational function into its
binomial parts, then expressing this in exponential form as a summation. One can then

Figure 12 Improved matching filter for better discrimination of signal from noise.