Cadence Environment, Digital Oscilloscope, Signal Conditioning Circuit Simulation And Realization Of Research

The task is to deal with the channel signal, which is one part of research and manufacture the 100MHz bandwidth Wideband Digitizing Storage Oscilloscope (WDSO). The signal processing, including circuits of channel 1, channel 2,exteral channel, trigger channel and control circuit of the channels, will do such jobs as amplifying, attenuating and flitting the signal of channels.In channel 1 and channel 2 circuits, we use three amplifiers and two attenuators to adjust the output signal's peak value to 1000mv. The gain of the channels can be changed and the –3dB bandwidth of the channels are 100MHz.The trigger circuit can produce trigger pulse relating with the input signals, whose amplitude and wave need to reach our demand. The trigger signals come from different channels. How to turn the signals into acceptable trigger pulse is the task of the trigger circuit, which includes trigger source choice circuit, coupling types choice circuit, trigger amplifier and comparator.The channel control circuit that accepts the MPU's information of mainboard and outputs many control signals is the overall console of the channel. It makes the entire channel works together. We use CPLD chip to realize the channel control function.In this design, we use the OrCAD to simulate circuits and modify the circuits basing on the simulate result.We employ many ultrahigh frequency operational amplifiers in this design that can be divided into two types: voltage feedback amplifier (VFA) and current feedback amplifier (CFA). We will discuss the applying of high-speed operational amplifier basing on the types briefly.With the IC switch speed and the density of the PCB boosting, signal integrity has become one of the issues we must concern in high-speed PCB design. Today, simulation is a necessity but not a choice to most PCB design, so we simulate the circuits with Cadence in the design too.