A performance information analyzer wherein one of tone pitch information data applied thereto in response to progress of performance of a musical tune is analyzed into one of plural performance parts on a basis of a difference in tone pitch between the one of the tone pitch information data and a reference...http://www.google.co.uk/patents/USRE38477?utm_source=gb-gplus-sharePatent USRE38477 - Performance information analyzer and chord detection device associated therewith
