A method for fast tracking and jitter improvement in an asynchronous sample rate conversion includes a digital phase locked loop (DPLL) for an asynchronous sample rate conversion (ASRC) device. A control apparatus in the DPLL includes a gain controller that sets and maintains gains (Ki, Kp) of two branches of the control apparatus at a fixed value, which enables searching of a desired value by the DPLL to determine a neighborhood of the desired value, and reduces the gains when the number of samples reaches a predetermined number. Processing units in the DPLL generate and process first and second input signals based on an input clock, an output clock, and a system clock. The second input signal is processed using two branches. Signals resulting from the two branches are re-aligned according to a changed status of the first processed input signal such that the signals resulting from the two branches are sampled in the same input clock interval.