带宽是示波器的重要指标之一，和放大器带宽定义相同，即所谓-3dB点，在示波器输入端输入正弦波信号时，幅度衰减至原信号幅度的0.707倍的那个频率点，称之为示波器带宽手持数字示波器。也就是说，假如一个示波器的带宽为100MHz的话，用它测试一个频率为100MHz，振幅为1Vpp的信号时，最后所测的信号幅度只有100MHz，0.707Vpp了。
示波器带宽指的是正弦输入信号衰减到其实际幅度的70.7%时的频率值，带宽决定着示波器对信号的基本测量能力，随着信号频率的增加，示波器对信号的准确显示能力将下降。如果没有足够的带宽，示波器将无法分辨高频变化，幅度将出现失真，边缘将会消失，细节数据将被丢失，得到的关于信号的所有特性都是没有意义的
数字示波器用于什么行业，它的组成部分，原理。
不知道你英文好不好 这是我是写的文章
The Basic Composition of Digital Oscilloscope
We know as long as we control the voltage which on X-axis and Y-axis deflection boards on digital oscilloscopes, we can control the graphic shapes on CRT display. An electronic signal is the function of time f（t）, which changes with time. Therefore, we can plus a voltage which is proportional with the time variable of the X-axis on CRT, and plus test signals on Y-axis, the graphics which are produced by the measured signals change with time. Among the electronic signals, the signal is proportional with the time variable in a period of time which is called sawtooth wave.
Digital oscilloscope is consisted of CRT, X-axis, Y-axis, Z-axis system and power supply.
Test signal ①was accessed to \"Y\" input terminal, and appropriate weakened by attenuator of Y-axis, then was sent to the Y1 amplifier (preamp), then push-pull output signal ②, ③. Through delay class to Y2 amplifier will be have a delay timeГ1. After amplifying it generate amplified signal ④, ⑤, added to the Y-axis deflection board on CRT of digital oscilloscope. In order to display the signal stable and completely, we can make the test signal③ access to the trigger circuit of the X-axis system, when we lead into positive or negative of the signal, and produce trigger pulse, then switch on sawtooth wave scanning circuit(time base generator) and produce scanning voltage⑦. As there is a period of time for delayГ2 from trigger to switch on scanning, ensure X-axis have started scanning before the signals of Y-axis are sent to the screen, so the delay timeГ1 which on X-axis should slightly larger than the delay timeГ2 which on X-axis. The scanning voltage⑦ through the amplifier of X-axis and amplified by the amplifier, push-pull output ⑨, ⑩ then adding ⑨, ⑩ to the X-axis deflection board on the CRT. Z-axis system is for amplifying scanning voltage on the way, and changing it to positive rectangular wave, at last send them to the gate of CRT on digital oscilloscope. This makes the waveform has a fixed luminance and wiping traces scan in return.
These are the basic parts of digital oscilloscopes. Dual trace show is using the electronic switch to display the two different signals which are input from Y-axis. As the function for human’s eyes have persistence of vision, when converting high frequency to a certain extent, we will see two stable and clear signal waveforms.
Digital oscilloscopes always have a square-wave generator of accuracy and stability, just for verifying the oscilloscopes.
如果你还想要更多关于示波器的资料 可以在google上直接搜我的用户名可以看到我写的关于这个的文章。
主要用于电子行业进行信号测量。
