It was invented around the 1920s, and the inventor, Léon Theremin -- he also was a musician besides an inventor -- he came up with the idea for making the theremin, I think, when he was working on some shortwave radios.
이건 1920년대에 '리옹 테레민'이라는 발명가에 의해 발명되었어요. 사실 그는 발명가이기 전에 음악가였죠. 그가 테레민을 만들려고 한 발상은 단파라디오의 신호를 맞추다 생각난거래요.