The Hammond Organ

The Hammond organ was introduced in US Patent 1,956,350. A difference between the Hammond organ and Telharmonium is that Telharmonium tones were something like ``bandlimited square wave'' tones (see Fig.G.1), while the Hammond organ tone wheels were carefully machined to provide nearly sinusoidal components. Thus, the Hammond organ truly classifies as an ``additive synthesis device'' (§G.8). It has survived essentially intact to the present day, and has been extensively simulated electronically (e.g., in Korg synthesizers).

Figure G.3: Tone Wheels of the Hammond Organ.