1. The noumenon part narrates the rhythm main structure rule of"Modal rhythm", "Mensural rhythm"and"Isorhythmic", moreover each chapter briefly summarizes the main body content.

2. In music and music theory, the Beat is the basic unit of time, the pulse (regularly repeating event), of the mensural level (or Beat level).

3. Alla Breve, the time signature 2 2, takes its name from the note value Breve.In the mensural notation of the Renaissance, it was an alternative term for proportio dupla, which meant that the brevis was to be considered the unit of time (), instead of the usual semibrevis.The old symbol