Past, current, and future trend in reconfigurable transceiver research and development

In 1990's a concept of software-defined radio has been proposed by Mitola. A reconfigurability of the operating parameters; center frequency, bandwidth and power level in transceivers only altered by software is one of the most important features in the software-defined radio to realize a versatile transceiver. Here we will review research and development in the field of reconfigurable transceiver, and discuss the future trend of this technology. In addition, our work of direct sampling receivers will be introduced on the context of reconfigurability of several characteristics such as image rejection, pass-band widening, etc.