Pulse width modulation amplifier

A pulse width modulation amplifier comprising:

• an envelope detector for detecting an envelope of digital data to be input;
• a level detector for detecting a level of the digital data from an out put of the envelope detector;
• a carrier generator for generating a carrier signal that successively increases a frequency corresponding to a detection result by the level detector;
• an interpolation data generator for generating interpolated data synchronous with the carrier signal from the digital data;
• and
• a converter for converting the interpolated data to a pulse width modulation signal based on the carrier signal.

A pulse width modulation amplifier comprising:

• a level detector for detecting a level of digital data to be put and outputting a detection signal when the level of the digital data becomes smaller than a predetermined value and remains smaller for a predetermined time;
• a carrier generator for generating a carrier signal that increases successively synchronous with an input timing of to digital data and, to carrier signal successively increasing having a frequency higher than the input timing when the detection signal from the level detector is received;
• an interpolation data generator for generating interpolation data synchronous with the carrier signal from the digital data;
• and
• a converter for converting the digital data to a pulse width modulation signal based on the carrier signal.

A pulse width modulation amplifier comprising:

• a level detector for detecting a level of digital data to be input;
• a carrier generator for generating a carrier signal that increases successively synchronous with an input timing of the digital data;
• and
• a converter for converting the digital data to a pulse width modulation signal based on the carrier signal, and for outputting a duty and a frequency fixed signal, when a detection result by the level detector is zero data, direct current data, or a small amount of data and the data is continuous.

A pulse width modulation amplifier comprising:

• an absolute value output circuit for outputting an absolute value of digital data to be input;
• a period data output circuit for outputting period data corresponding to the absolute value from the absolute value output circuit;
• a carrier generator for generating a carrier signal that successively increases a frequency corresponding to the period data;
• and
• a converter for converting the digital data to a pulse width modulation signal based on the carrier signal.