Out of curiosity, I was noticing hi-pitched sweep in some old Japanese animation (Serial Experiments LAin; Fushigi no Umi no Nadia; Kimagure Orange). Example voiceprint: http://i.imgur.com/G7dGgV2.png
Hi chkktri, Stavrosound is right, the high frequency you can hear is most probably due to the fact that they used an old CRT TV in the studio. The CRT tube creates what's known as 'line whistle' which is a single tone at a frequency of 15.625kHz for PAL territories and 15.734kHz for NTSC. This can easily be notched out by using a very narrow notch filter on max attenuation. It's probably best to gain the notch and sweep around the frequency, until the whistle is amplified, then at maximum level, cut the frequency to max which will get rid of this annoying high frequency.