TRANSMITTER

摘要

A transmitter capable of amplifying even a wide dynamic range signal with high efficiency and low distortion. The transmitter has a level separator for separating an envelope signal into a signal not less than a reference level and a signal less than the reference level according to the signal level of the envelope signal, a first pulse width modulator for performing the pulse width modulation of the signal not less than the reference level to form a first pulse width modulation signal, a second pulse width modulator for performing the pulse width modulation of the signal less than the reference level to form a second pulse width modulation signal, a first transistor to which a first applied voltage is supplied and which allows the first pulse width modulation signal to switch over the first applied voltage for output, a second transistor to which a second applied voltage smaller than the first applied voltage is supplied and which allows the second pulse width modulation signal to switch over the second applied voltage for output, and a smoothing circuit for smoothing the combined signal of the output signals of the first and second transistors to output it to the power supply terminal of a power amplifier.