added circuit

I added the trigger circuit to the DSO. 3.

增加了触发的硬件电路, 完善了本款示波器的触发的方式.

They added these circuit boards to the computer main board.

他们将这些电路板加工成电脑的主板.

Phase shifter is added into the oscillator, forcing the working frequency of the sensors close to the center frequency, so the stability and the dynamic range of the oscillation circuit are improved.

在原有振荡电路中增加了移相环节，使传感器工作在中心频率下，提高了振荡电路的输出稳定度及动态响应范围。

PFW was added based on PWM, and switching circuit between PWM, PFW and control circuit of external characteristic were designed, the control system fulfilled the higher request, and have double excellence of PWM and PFM.

在PWM控制的基础上引入PFM控制，并设计出PFM与PWM的切换电路及外特性控制电路，实现了设计的控制要求，使整个控制系统具有PWM和PFM的双重优点。

I added the trigger circuit to the DSO. 3.

增加了触发的硬件电路, 完善了本款示波器的触发的方式.