The S.O(synchronous osillator) oscillates at its natural frequency without the externa applied signal. But if the external signal is applied, the S.O starts to track the external frequency which can be sinusoidal, pulsed or some other waveform. Thus, the output is synchronized with the wide range of tracking bandwidth to the external frequency. Specifically, the S.O also posses frequency division and multiplication capability. All of these indicate that the S.O can overcome the difficulties of syschronization in coherent digital communication systems. This papers proposed application of DS/SS communication with study on the synchronous properties of S.O.