Software radio is an emerging technology, thought to build flexible radio systems, multiservice, multistandard, multiband, reconfigurable and reprogrammable by software. The flexibility of a software radio system consists in its capability to operate in multiservice environments, without being constrained to particular standard, but able to offer, services of any already standardized systems or future ones on radio frequency band. The presence of the software defining the radio inter face necessarily implies the use of DSPs to replace dedicated hardware to execute, in real-time, the necessary software. Digital communication standard are generally based on different master clock rates. Thus sample rate conversion is required in systems that possess signals of different communication standards..