1) Echo 2) Recurrence 3) Repetition 1) Reduplication 2) Repeating 3) Repetition 
• (n.) The act of reiterating; that which is reiterated.
the repetition of the signal elements of a given digital signal to change the digit rate from its original value to a value which is an integral multiple of the original digit rate NOTE - The associated verb is 'to reiterate'.
Re·it`er·a'tion noun [ Confer French réitération .] The act of reiterating; that which is reiterated. 
reiteration 1. The act of repeating over and over again or an instance of such action. 2. To say or to do again or repeatedly. 3. To repeat excessively again and again.