5 The Gsps Lxi Oscilloscope Module Hardware Design

With the development of science and technology and the demand for testing methods, the digital storage oscilloscopes with the advance functions are wildly used in the testing field. LXI based oscilloscope has many merits, such as high throughput, simple connection, friendly programming environment, and high synchronization precision, it broad application prospects in the field of distributed test. However, the development of LXI base oscilloscope has lagged behind the similar foreign products. It is very necessary to design high sampling rate LXI based oscilloscope.This dissertation is to design the hardware of LXI based oscilloscope with5GSPS. We will focus on the signal processing circuits, control circuit for data acquisition and storage, LXI interface circuit. The main works are as following:1、the design of signal processing circuit. The signal processing circuit consists of signal channels and trigger channel. The signal channels are used to attenuate and magnify the input signal and make the input signal to be within the input range of ADC. The signal processing circuit is also used to make the input signal moveable in vertical axis. Trigger circuit provides a trigger signal for stabling displaying signal.2. the design of control circuit for data acquisition and storage. The5GSPS data acquisition is implemented by two FPGA, one ADC, time interleaved sampling technique. The functions of FPGA include:channel control, ADC control, PLL control, storage control, time-base control, data storage, address decoding.3、the design of LXI interface circuit. DM9000E MAC chip, DP83848PHY chip and the accurate clock synchronization module are employed to implement the LXI interface.After a year of analysis, design and debug, the indicators, and functions all meet the design requirements.