Research On IF Signal Processing Technology Of Sampling Oscilloscope

As technologies such as 5G communication and optical fiber communication are gradually becoming the most popular research directions in the field of communication,schools and enterprises urgently need low-cost,high-precision broadband signal test solutions.Because of the use of the equivalent sampling technology,sampling oscilloscope's bandwidth,equivalent sampling rate and other indicators can easily meet the test requirements,therefore,this kind of instrument is widely used to test lightwave signals and high-speed digital Signal.It can be said that sampling oscilloscope is an indispensable instrument of modern electronic testing.The IF(intermediate frequency)signal processing module is one of the key parts of the sampling oscilloscope.In accordance with the design requirements,this paper designs every part of the circuit of the IF signal processing module according to the port characteristics of the sampler and the characteristics of the sampler output signal,then adjusts it to the sampler module,finally tests and analyze the test results to prove the feasibility of the circuit design.The main work completed in this paper is as follows:First,based on the overall hardware solution of the sampling oscilloscope,the basic workflow of each module composition and the waveform reconstruction of the whole machine is analyzed,and the position and function of the module designed in this paper in the whole machine are clarified accordingly,and then the intermediate frequency signal processing is clarified how does the module convert the pulse signal output by the sampler into a signal that meets the input requirements of the subsequent circuit.Secondly,on the basis of the basic principles,port characteristics of the sampler studied,and the design theory and design ideas related to the analog intermediate frequency signal processing circuit,the high-impedance integration circuit,the dual conversion single-ended circuit and the IF filter amplifier circuit are designed.And the high-impedance integration circuit and the IF filter amplifier circuit were both simulated and tested on the test board to verify its normal function and meet the system requirements;according to the design requirements,the vertical offset control hardware circuit and the whole board power supply circuit were designed.Finally,considering the factors such as the installation position of microwave components and semi-rigid wiring,the IF PCB is designed,and the circuit board is debugged and tested.The test results show that the hardware circuit board cooperates with a high-bandwidth sampler to sample,wave transform,and 35.5dB amplify and filter the signal to be tested from 310 KHz to 20 GHz,and generate an IF signal with a maximum frequency of 160 KHz,which meets the requirements of the subsequent circuit.