Jean Khawand

Method and apparatus for generating percussive sounds in embedded devices

A percussive sound contains both harmonic and non-harmonic frequency spectral content. To reproduce a particular percussive sound, such as the sound of a drum or cymbal or hand clap, for example, the harmonic and non-harmonic content are determined empirically. Also, and tendency of the harmonic content to change over time, and the temporal aspects of attack, sustain, and decay are likewise determined empirically. These attributes are represented in the invention in a percussive sound file which includes a harmonic content profile (502), noise shape filter (504), Doppler shift profile (506), and a time wave shaping profile (508). The harmonic content profile is used by an FM generator (114) to generate a frequency modulated signal (116). The noise shape profile is used by a noise generator (134) to generate and shape the non-harmonic spectral content. While the sound is being generated, the Doppler shift profile is used to adjust the base frequency of the FM signal. The harmonic and non-harmonic signals are scaled (142, 144) and summed (146). The summed signal is then shaped (150) in time to substantially simulate the attack, sustain, and decay properties of the sound. The shaped, summed signal is then played by an audio circuit and converted to an acoustic signal.