Adaptive phase-locked loop operating in the pseudo-linear region

An adaptive second-order phase-locked loop is proposed which keeps the loop within the pseudo-linear region for a wide range of input frequency steps. FETs are used to vary the filter transfer function as well as the overall loop gain, thus yielding almost linear behaviour. Theoretical analysis of the proposed system has been carried out, and the system has been constructed to show that it is possible to increase this region for the loop from a frequency step of 353.5 rad/s to 3535 rad/s without affecting its noise-rejection property.