Harmonic synthesizer

32-component synthesizer used by Dayton Miller







Lord Kelvin's harmonic synthesizer is basically Henrici's harmonic analyzer in reverse. Originally designed as a tide predictor in 1873, the system can combine numerous component waves—in some devices, up to 64 separate components—into a single curve. It is based on the earlier pin-and-slot device, which produces simple harmonic motion with the turn of a crank.

The version used by Dayton Miller was designed and built in the laboratory and instrument shop of the Physics Dept. of the Case School of Applied Sciences. It consisted of 32 rotating pin-and-slot devices (see diagram below), each of which produced simple harmonic motion with a specified amplitude and phase; these 32 elements controlled the motion of a single cable that traced out the combined wave with a stylus and sliding drafting table. It was used by Dayton Miller to check the results produced by the harmonic analyzer against the original phonodeik curve. This device is no longer in the CWRU Physics Dept. collection.