We demonstrate an all-electronic digital-to-analog converter (DAC) with 100-GHz electrical bandwidth, sampling at 240 GSa/s, based on digital band interleaving (DBI). We discuss digital predistortion techniques for compensating the nonideal performance of the high-speed and radio-frequency components in our DBI architecture. We then test the DAC by generating up to 190-GBaud Nyquist-shaped pulse amplitude modulation. We analyze the performance of the digital band interleaved DAC and demonstrate coherent detection of single-polarization optical binary phase-shift keying at 140 GBaud.