Synthesizer for transmitter and digital amplitude modulator

A digital amplitude modulator, comprising:

• a plurality of power amplifiers which are arranged in parallel and turned on or off in accordance with a voltage amplitude level of a signal to be modulated to amplify power of a predetermined signal;
• and
• a synthesizer which syntheses outputs from the power amplifiers to generate an amplitude-modulated wave;
• wherein the synthesizer comprises:
• a transformer including a primary winding connected to each the power amplifiers, and a secondary winding which opposes the primary winding;
• a plurality of core support units including a support plate which supports a toroidal core around which the primary winding is wound, fixing unit which fixes the toroidal core to the support plate, and an insertion portion which is formed inside or around the toroidal core and into which the secondary winding is inserted;
• and
• a fixing member including a plurality of receiving portions to and from which the plurality of core support units are attached and detached,
• wherein the plurality of receiving portions are formed along a direction in which the plurality of core support units are stacked.