Design And Implementation Of Digital Signal Processing Module Of Sampling Oscilloscope

Sampling oscilloscope having high bandwidth and sampling rate can measure high speed fast electronic signal. Digital signal processing(DSP) module of sampling oscilloscope is an essential part of sampling oscilloscope. This dissertation describes the basic frame of sampling oscilloscope, and then describes the design and implementation of digital signal processing module in the instrument. The contents of the module in general can be divided into the design and implementation of the hardware of the module, the design and implementation of its software. From the specific functions, contents can be divided into communication with the host computer, control of the underlying acquisition system, receiving and processing the original data from the acquisition system, bootloader.The hardware design of the module includes the establishment of minimum system, network communication between personal computer(PC) and DSP, through the external memory interface and general purpose input output(GPIO) to communicate the acquisition system. The digital signal processing platform is based on Texas Instruments(TI) company’s TMS320C6747. The platform has a rich peripheral set such as network interface, external memory interface, USB, UART and SPI. Thus the platform can fulfill the design requirements. The design workflow is designing the hardware schematics, fabricating the printed circuit board(PCB) and debugging PCB. The debugging is divided into single board debugging and the on-line debugging. The single board debugging contents mainly include the debugging of network module, interruption and BOOT module. The on-line debugging contents include the shake hands with the communication between the platform and the underlying FPGA and control of the acquisition system of the instrumentation primarily.The software design uses DSP/BIOS kernel as operating system(OS). The software design includes development of network communication with network development kit(NDK), a multi-threaded program that can execute concurrently and bootloader. The multi-threading has a parent thread and two children threads. The parent thread works as a daemon thread of the network server, and has been working until the system shutdown. The two child threads can parse network commands, communicate with the underlying FPGA.Since the time base error of the high speed sampling oscilloscope caused imperfect measurement rusults, the dissertation describes the time base error. The time base errors include the time-base jitter and time-base distortion. This design uses the total average method to deal with random noise, and uses sine-fit method to estimate time-base distortion.After evaluation, the performance of this design meets the design requirements. The design realizes basic functions of sampling oscilloscope, as well as estimates the time-base distortion.