To adjust or adapt the pitch, tone, or volume of sound. The singer modulated her voice to match the mood of the song.
To regulate or adjust a process or system. The engineer modulated the flow of water to ensure the system operated efficiently.
To change from one key to another in music. The composer decided to modulate from C major to G major in the middle of the piece.
To alter the amplitude, frequency, or phase of a waveform in electronics. The technician modulated the signal to improve the quality of the transmission.