Portable Digital Oscilloscope Design

This thesis describes the system architecture of the portable digital storage oscilloscope . The basic modules are also designed and researched. On the base of analysis about the adaptive amplitude control of the analog signal channel, Butterworth filter, error signal pick-up, frequency mensuration, super-speed A/D (Analog signal /Digital signal) conversion, data storage, LCD (Liquid Crystal Display) display format conversion and the LCD control circuit, the analog signal channel preceding A/D conversion is researched detailedly and the relative problems and the solutions are brought forward in realizing the control for the large signal amplitude change and in realizing the mensuration for the wide-range frequency. The hardware design works such as attenuators, operational amplifiers, low frequency signal pass filter, error signal pick-up, CPLD application, CPU control circuit etc. are achieved. The software design works including the assemblings and tests about MC-51 language,C51 language,VHDL language are finished as well. In the part of the frequency mensuration, the reason of the mensuration error is analysed, and the exact synchronization between timing and counting signal is also achieved with the help of CPLD.