FIVE VARIATIONS ON A FEEDBACK THEME

This is a study on a set of feedback amplitude modulation oscil- lator equations. It is based on a very simple and inexpensive al- gorithm which is capable of generating a complex spectrum from a sinusoidal input. We examine the original and five variations on it, discussing the details of each synthesis method. These in- clude the addition of extra delay terms, waveshaping of the feed- back signal, further heterodyning and increasing the loop delay. In complement, we provide a software implementation of these algorithms as a practical example of their application and as demonstration of their potential for synthesis instrument design.