说明：  ISD1420为美国ISD公司出品的优质单片语音录放电路，由振荡器、语音存储单元、前置放大器、自动增益控制电路、抗干扰滤波器、输出放大器组成。一个最小的录放系统仅由一个麦克风、一个喇叭、两个按钮、一个个个电源、少数电阻电容组成。录音内容存入永久存储单元，提供零功率信息存储，这个独一无二的方法是借助于美国ISD公司的专利——直接模拟存储技术（DAST TM）实现的。运用它，语音与音频信号被直接存储，以
(The ISD1420 United States ISD produced high-quality single-chip voice recording circuit, by the oscillator, the voice storage unit, preamplifier, automatic gain control circuit, anti-interference filter, the output amplifier. A minimum recording system only by a microphone, a speaker, two buttons, one all power, a few resistors and capacitors. Recording the content deposited in the permanent storage unit, providing zero-power message storage, this unique approach is by means of the patent of the United States ISD- direct analog storage technology (DAST TM). Use of it, voice and audio signals are stored directly to)