Some basic properties of the time-sidelobe of arbitrary sequence’s auto-correlation function have been studied and several theorems of the time lobe are also proved in the paper.Some practical examples are taken using the theorems. The first example is to search low sidelobe codes

and the second example uses sidelobe’s self-complementary property to cancel sidelobe of 63 bit PN code. The method for cancelling sidelobe needs only little add operation.