Digital Storage Oscilloscope 300mhz Analog Channel Design

Analog channels are pivotal part of DSO(Digital Storage Oscilloscope),their performance and index restrict the development directly.How to make the analog channels have wider frequency band,lower noise,better AC and DC performance is an important content in the process of DSO research,which making the design of analog channels is a sticking point for DSO design.This project is design of 300MHz analog channels,and signal conditioning channel,trigger signal channel,controlling and base adjusting circuit,restraining noise and anti-jamming design are included in this project.The new frame of DSA(Digital Step Attenuator)+ high-speed OP+ fixed gain OP+ differential OP is adopted in the signal conditioning channel design,which making the bandwidth reach to 300MHz,add the stability of the circuit and reduce the difficulty of debugging.More advanced analog multiplexer,video sync separator,high-speed comparator are Chose in trigger signal channel design and higher performance trigger signal,more simple circuit are obtained.The base adjusting range is expanded to±1V (2mV/div—200mV/div) and±20V(500mV/div—5V/div) because particular base adjusting circuit is Used.The cost is saved for using low resolution DAC.The IC with output latch is selected to control channel,and possibility of incorrect operation is reduced.More attention is paid to restraining noise and anti-jamming in this design, such as filtering circuit,PCB design.Many important theories are applied in this design,such as impedance match, high-speed PCB design and high-speed amplifier application.