Transmitter

A signal transmitter, comprising:

• a modulated signal generating means that generates a modulated signal;
• an amplitude slicing means that slices an amplitude component of said modulated signal at a plurality of voltage levels which are stepwisely different;
• a first and a second plurality of switching regulators that convert a supply voltage into a plurality of voltages whose values are stepwisely different;
• a first switch group that selects any one of output voltages of said first plurality of switching regulators;
• a second switch group that selects any one of output voltages of said second plurality of switching regulators;
• a switch driver that selectively makes a conduction of each of switches of said first and said second switch group according to slice data of the amplitude component sliced by said amplitude slicing means;
• an amplitude amplifying means that amplifies said amplitude component using an output voltage of either of said switching regulators selected by said first switch group as a supply voltage;
• a linear DC converting means that performs a DC-conversion of an output from said amplitude amplifying means using an output voltage of either of said switching regulators selected by said second switch group as a supply voltage;
• and
• an RF power amplifier that receives said modulated signal or its phase component to an RF input terminal, receives an amplitude component to which the DC-conversion is performed by said linear DC converting means to a power supply terminal, and eventually outputs a modulated wave.