Implementation of sample rate conversion in direct RF synthesis transmitter

In software defined radio (SDR) transmitter, the baseband data with protocol-specific symbol rate should be up-sampled to the fixed sample rate of synthesized carrier by arbitrary sample rate conversion (ASRC), before up-conversion. During the last few years, along with the rapid development of DAC technology, it is possible to implement direct RF synthesis using digital method. This paper presents implementation structure of a two stage SRC in FPGA, which can be used in Direct RF synthesis transmitter to interpolate the baseband data of variable symbol rate to RF sample rate.