Transmission device and radio communication device

A transmission apparatus using a polar modulation scheme, comprising:

• an amplitude phase separation section that separates baseband modulation data into a baseband amplitude modulation signal and a baseband phase modulation signal;
• a phase modulation section that modulates a high frequency carrier signal based on the baseband phase modulation signal and forms a high frequency phase modulation signal;
• a variable gain amplification section that is provided in a later stage of said phase modulation section and amplifies the high frequency phase modulation signal;
• and
• a high frequency power amplifier that is provided in a later stage of said variable gain amplification section and amplifies power of the high frequency phase modulation signal amplified by said variable gain amplification section,
• wherein said variable gain amplification section comprises:
• a linear-log conversion circuit that linear-log converts the baseband amplitude modulation signal;
• and
• a variable gain amplifier that amplifies the high frequency phase modulation signal based on the linear-log converted baseband amplitude modulation signal and a gain control signal.