“喇叭筒”的英语？

控制器通常有错误发现者和喇叭筒.The controller usually consists of an error detector and amplifier.他用喇叭筒叫卖, 省劲多了!He hawks with a megaphone, saving a lot of effort.喇叭筒对于使用西元574A应该 在500仟赫有可接受的环增益.The amplifier should have acceptable loop ...