A compact disc player for portable use requires a good rejection of disturbances and an accurate position of the optical reader sensor. The position control system uses unity feedback and a loop transfer function

The parameter p can be chosen by selecting the appropriate DC motor. Sketch the root locus as a function of p. Select p so that the ζ of the complex roots of the characteristic equation is approximately 1/ˆš2.

10 L(s)-Gc(s)G(s) -s(s + 1)(s + p)