An envelope tracking (ET) system is provided. The ET amplifies a radio frequency (RF) signal correspond to an amplitude bandwidth exceeding a voltage modulation bandwidth limitation of the ET system. The ET system compresses the amplitude bandwidth to match the voltage modulation bandwidth of the ET system. More specifically, the ET system compresses a predefined voltage waveform, which tracks time-variant amplitudes of a digital form of the RF signal, to generate a modified voltage waveform at a reduced bandwidth. To ensure that signal distortion(s) resulted from the bandwidth compression can be corrected, the ET system nonlinearly modifies predefined amplitude(s) of the predefined voltage waveform to generate modified amplitude(s) of the modified voltage waveform that is never less than the predefined amplitude(s) of the predefined voltage waveform. As such, the ET system can amplify the RF signal with improved linearity and efficiency, without degrading spectral performance of the RF signal.