A quadrature-based phase-locked loop

A method of synthesizing quadrature-based phase-locked loop is presented. The method is based on a quadrature-signals principle wherein the detector output contains only phase/frequency difference, which, in the form of an error signal, is applied to the loop filter. This is in contrast to the error signal of a standard phase-locked loop comprising both the sum and the difference of the input and output respective phases/frequencies. The quadrature-based phase-locked loop imposes less requirements on the loop filter making it feasible to acquire and maintain the lock using the filter of the smaller order, with less stability problems.