# AM & Ringmodulation: Introduction

Amplitude modulation (AM) and Ringmodulation are essentially the same technique, yet with a slight variation. For both, formula and signal flow diagram are the same:

$\displaystyle y(t) = x(t) \cdot m(t)$

Ringmodulation is an audio effect, used since the early days of analog sound synthesis and electronic music. Karlheinz Stockhausen used the ringmodulator in various works as an instrument, as for example in Mixtur (1964):