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But here's a mystery:
但這里有個小謎團:
When you press pause on the VCR, the screen doesn't go blank.
當你按下錄像機的暫停鍵,屏幕并不是一片空白。
Instead, you get a frozen image.
相反,你看到的是停止的畫面。
Remember,you need a changing magnetic signal to create even a still video image.
記住,你需要改變的磁信號創建靜止的視頻畫面。
If the video tape isn't moving, where is this changing signal coming from?
如果錄像帶沒有向前播放,這個改變的信號來自哪里?
We're used to VCRs doing this, but it's actually kind of strange.
我們習慣了錄像機這樣的工作方式,但實際上有點奇怪。
It would be like pressing pause on a cassette deck and having the sound remain in your speakers,Pavarotti holding his high C until you press play again.
這就像在錄音機上按下暫停,聲音仍然在你的揚聲器中,帕瓦羅蒂的高音C會等你再按播放才開始。
VCRs do this trick by moving both the tape, AND the playback heads, which spin rapidly past the tape as it moves through the machine.
錄像機的這個小秘密是通過帶子向前播放及整個機器中滑過帶子的放音磁頭實現的。
Pausing a video tape does indeed stop the tape, but it doesn't stop the spinning playback heads.
暫停確實使帶子停止,但沒有停止放音磁頭。
These continue to swipe past the stationary tape, detecting enough of a magnetic signal for one still frame of video.
放音磁頭繼續通過靜止的帶子,因此偵測到的足夠磁信號就產生了靜止的視頻畫面。
Modern, hi-fi VCRs automatically mute the sound when they are paused, so you don't get a sustained audio sound as well!
現代高保真錄像機會在暫停的時候自動將聲音靜音,這樣就不會聽到持續的聲音!
