Design Of Control Module Of Descrete Magnitude For Digital T/R Tester

Nowadays society has been a continuous rapid development of information society.Along with the advanced technology constantly emerging, test instruments have been updated to meet the testing requirements of new instruments.Digital T/R test instrument is realized by using digital circuit design to test the receiving and dispatching module performance by modern automatic test system. Its design adopts the most popular modular design thought in the automatic test system. Its system control test section can be divided into three modules: control computer, signal adapter box and accused of testing instrument. Through discrete quantity control module to control four test module in the system control test section.The discrete magnitude control module design of digital T/R test instrument mainly includes the data receiving and processing. The means of implementing this design is through the module hardware circuit design and FPGA logic circuit design.From the part of hardware circuit design, the discrete magnitude control module can be divided into three parts: the USB interface and peripheral circuit, FPGA and peripheral circuit, output circuit. USB interface and peripheral circuit complete the data transmission of the computer and the discrete magnitude control module, plays an important role in the information communication. FPGA and peripheral circuit complete the function of data processing, accept data from the USB interface for processing,translate into RS485, LVDS, to/open discrete magnitude and the power to/open discrete magnitude four modules to output control signals. Output circuit translates the control signal which comes from FPGA into the output control signals of discrete magnitude control module.The FPGA logic circuit design including the USB data receiving, processing of receiving data and output circuit. USB data receiving module transmits the data which comes from the USB interface to the FPGA. Receive data processing module is to allocate the received data according to the address bits in accordance with the data structure definition. Output circuit module will turn processed data into a corresponding control signal output. The LVDS modules include HDLC module and the LVDS output module. In the HDLC module, data will be transmitted to meet the HDLC protocol information. The LVDS output module has two kinds of model output, a model outputin HDLC signals, another mode output switch magnitude. RS485 module choose three kinds of timing signal to output according to the data.Discrete quantity control module design need to be test to complete debugging and validation. Results of debugging and verification show that the discrete magnitude control module is able to realize the control signal output function, running stability, and achieved the expected design goals.