Old spec 5.3 numerical example, Bode diagram of a first order systemTutorialOld spec ENGR2022:210 min

ENGR202 (old spec) Control 5.3 Frequency Response Revisited, Bode diagram numerical example (slides 13-14)

For the first order system G(s)=11+3sG(s) = \dfrac{1}{1 + 3s}, find general expressions for the magnitude MM and phase ϕ\phi of the frequency response, then complete a table of MM, log⁡10M\log_{10}M and ϕ\phi (radians and degrees) at ω=0\omega = 0, 1/31/3, 1, 10 rad/s and ω→∞\omega \to \infty, and describe the Bode diagram.

Formulas you may need
  • M=∣G(jω)∣M = |G(j\omega)|, ϕ=Arg G(jω)\phi = \mathrm{Arg}\,G(j\omega); ∣z1/z2∣=∣z1∣/∣z2∣|z_1/z_2| = |z_1|/|z_2|, Arg(z1/z2)=Arg z1−Arg z2\mathrm{Arg}(z_1/z_2) = \mathrm{Arg}\,z_1 - \mathrm{Arg}\,z_2 (learn this)
  • Corner frequency ω=1/τ\omega = 1/\tau, where log⁡10M=log⁡10K−0.15\log_{10}M = \log_{10}K - 0.15 and ϕ=−45∘\phi = -45^\circ (learn this)