Although audio tapes and video tapes look different, they're based on the same principles.
尽管磁带和录像带看起来不同,但二者都基于同样的原理。
Each has a roll of magnetic material which slides past the so-called “playback head” in the VCR or cassette deck (cassette decks have one playback head, VCRs have two or more).
录像机或盒式录音机(盒式录音机有一个放音磁头,录象机有两个或更多)都有能够滑过被称为“放音磁头”的磁性材料。
In both machines, these heads detect changes in magnetism as the tape moves by.
这两种机器的磁头都会随着本身媒体的运动检测磁性的变化。
The changing magnetic signal is translated into music on your tape deck, or both video and sound on your VCR.
磁信号的改变转化为你录音机中的音乐,或录像机的视频和声音。
Without a changing magnetic signal over a playback head, you'd get no sound, no picture.
如果放音磁头没有磁信号的变化,你就得不到声音和图像。