2016.11.12−02.44.13TH 6 5 4 3 2 1 0 700 750 800 850 900 950 time (sec) 1000 1050 1100 1150 700 750 800 850 900 950 time (sec) 1000 1050 1100 1150 100 frequency (Hz) 80 60 40 20 0