The CZ-101 featured Casio’s original “PD sound source,” newly developed in the lead-up to Casio’s debut on the synthesizer market. PD, which stands for Phase Distortion, modified the phase angles of waveforms to generate complex overtones. Enabling tones to be produced with ease by anyone and everyone, the model opened the door for synthesizers—until then very difficult to operate and the province of only a specialized subset of users—to be enjoyed by many more people.