Tremolo 震音
In music, tremolo (Italian pronunciation: [ˈtrɛːmolo]), or tremolando ([tremoˈlando]), is a trembling effect. There are two types of tremolo.
The first is a rapid reiteration
A second type of tremolo is a variation in amplitude
Some electric guitars use a (somewhat misnamed) device called a "tremolo arm" or "whammy bar" that allows a performer to lower or raise the pitch of a note or chord, which is known as vibrato. This non-standard use of the term "tremolo" refers to pitch rather than amplitude. True tremelo for an electric guitar,electronic organ, or any electronic signal would normally be produced by a simple Amplitude modulation electronic circuit.