Design Of Portable Signal Analyzer Based On Virtual Instrument Technology

With the rapid development of wireless communications technology, the signal analyzer is always utilized when people design their communication systems. Signal analyzer is mainly used to analyze the modulated information involved in wideband signal, such as EVM, ACLR, and modulation bandwidth. The analyzer acquires the ADC data by using Digital IF Technology and then demodulates the original bitstream in softwares. The portable signal analyzer based on Virtual Instruments Technology combines high performance hardware and flexible PC software together to make it smaller and less expensive.The portable signal analyzer contains’hardware platform and software platform design. The hardware design can be divided into two parts, firt of all, the RF hardware part applied the superheterodyne receiver structure by using two mixers, with the first IF frequency at3.45GHz and the second IF frequency at 140MHz. The paper discusses the key performance indicators of the receiver, and there are many modules such as programmable attenuator, LO, mixer, low noise amplifiers, IF filters, RF switches, reference clock and so on. Then, the design of FPGA part with peripherals and 250Msps ADC module is mentioned in the paper. The software part mainly consists of Microblaze processor programming and Matlab GUI realization. In this paper, FPGA is developed with Xilinx SDK tool, and Matlab is used to design user interface on the computer.Finally, the test resaults shows that signal analyzer can detect the signal with the frequency ranges from 10MHz to 3GHz, and the input power covers between-80dBm and+30dBm. The software designed with Matlab GUI can display the signal spectrum and QPSK constellation after demodulation.