E. Carr Everbach
Dept. of Eng., Swarthmore College, Swarthmore, PA 19081-1397
Recent interest in automated pitch detection [J. Acoust. Soc. Am. 92, 2428--2430 (A) (1992)] has led to develop a device whose purpose is to transcribe the musical lines of single-voice instruments (e.g., flute, trumpet) in a MIDI format using Apple Macintosh(trademark) computers and software. In contrast with other devices requiring rapid digital sampling of the audio signal and extensive computational and digital signal processing resources, this is an essentially analog electronic device based upon a phase locked loop and matched filter that strips off the higher harmonics of the instruments' waveform. The signal that results is nearly sinusoidal, allowing the use of the Macintosh's own modest built-in digital sampling capabilities for transcription of the musical line played on the instrument into a MIDI format.