Journal Article
Applications of Current-Starved Inverters to Music Synthesis on Field Programmable Analog Arrays
Journal of the Audio Engineering Society · Volume 66 · Issue 1/2 · pp. 71–79 · January 2018
Abstract
Sound synthesis is often conceptually divided into modules that create or process audio, such as oscillators, filters, and amplifiers, and modules that generate control signals that vary parameters over time, such as pitch of oscillators, cutoff frequency of filters, and gain of amplifiers. Recent advances in field programmable analog arrays (FPAAs) that employ floating-gate transistors have opened the possibility of new analog music synthesizer designs with greater flexibility and higher levels of integration that merge audio processing and parametric control. This report describes implementations of voltage-controlled oscillators (VCOs) and envelope generators on FPAAs using current-starved inverters. VCOs can be used at audio rates or as low-frequency oscillators. Experiments conducted on an FPAA illustrate the modulation of the cutoff frequency of a voltage-controlled filter and the gain of a voltage-controlled amplifier implemented with a Gilbert multiplier.
