Emergency alarm of NHK (Japan's national public broadcasting organization)

Emergency alarm sound of NHK (Japan's national public broadcasting organization)
http://en.wikipedia.org/wiki/NHK

Caption 1:

1. low-grade alarm (used many times)

Caption 2:

2. moderate-level alarm (Showa Emperor (Hirohito) died in 1989, NHK used this alarm before that news)

Caption 3:

3. the highest level alarm. impose a state of emergency nationwide.
(News of the start of Pacific War)