Transmission circuit, and communication apparatus using the same

A transmission circuit for generating a transmission signal based on input data and outputting the transmission signal, the transmission circuit comprising:

• a signal generation section for modulating the input data to generate an amplitude signal representing an amplitude component of the input data and data of a predetermined form;
• a calculation section for performing a calculation using the amplitude signal and the data of the predetermined form, and outputting a discrete value having a level which is discrete at an interval of a predetermined time period, a first phase signal and a second phase signal;
• a first angular modulation section for performing angular modulation on the first phase signal, and outputting the resultant signal as a first angle-modulated signal;
• a first amplitude modulation section for performing amplitude modulation on the first angle-modulated signal with a signal in accordance with the level of the discrete value, and outputting the resultant signal as a first modulated signal;
• a second angular modulation section for performing angular modulation on the second phase signal, and outputting the resultant signal as a second angle-modulated signal;
• a second amplitude modulation section for performing amplitude modulation on the second angle-modulated signal with a signal in accordance with the level of the discrete value, and outputting the resultant signal as a second modulated signal;
• and
• a combining section for combining the first modulated signal and the second modulated signal, and outputting the resultant signal as a transmission signal;
• wherein the calculation section
• compares the amplitude signal and a plurality of threshold values and outputs a discrete value having a level which is discrete at an interval of the predetermined time period;
• and
• calculates a phase component of the data of the predetermined form and outputs the first phase signal having the phase component shifted in one direction by a predetermined phase and the second phase signal having the phase component shifted in the other direction by the predetermined phase.