Development Of60Msps PXI Bus Digitizer

With the development of integrated circuits, the test product becomes moremultifunctional and more miniature. In integration test system, the normalequipment can not be used due to large volume, therefore, modular instrument ismore and more popular. The digitizer as a modular instrument, using the PCprocessing technology, can complete the measurement which the oscilloscope,spectrum analyzer, transient recorder or other traditional instruments can do. Thedigitizer is widely used in the industrial, scientific and military fields etc, has a veryimportant role.The paper first introduces the task which the digitizer need to complete,according to its function and technical indexes, design the overall program of thedigitizer, and make a detailed analysis to key circuit options. The module usingFPGA as the master, high-speed DDR2SDRAM as cache, the PXI as instrument businterface, realized the digitizer which has10channels, and each channel highestsampling rate is60Msps. In the design, The analog channel has AC and DCcoupling selection,1MΩ/50Ω input impedance selection, programmableamplification and attenuation, high-speed storage part use the multi-chip DDR2SDRAM memory particles to achieve the large-capacity cache and the capacity isup to1GB, the maximum storage rate reached2.88GB/s; trigger circuit can achievethe same card multiple trigger source selection, and multiple board synchronizationtrigger; clock circuit realized the clock source selection and the clock multiplier anddivider; PXI interface circuit realized PCI interface and the PXI trigger design; PCBdesign used the IBIS model to achieved wiring and post wiring simulation to ensurethe integrity of the signal in two high-speed circuit of the system.In the design of the software, design the digitizer driver with VISA, design atest panel with LabWindows/CVI. The driver implements six major categories:system initialization functions, system configuration functions, data acquisitionfunction, set/get/check attribute function, measurement function, the calibrationfunction, utility function and error handler. The test panel can config and test thedigitizer fully. Finally, the tested results show that the instrument meets the task demands.The digitizer has a good expansibility, it can realize different acquisition functionby keep the storage motherboard and just changing the acquisition daughter board.