Design Of Multi-channel Acquisition,Encoding,Storage And Transmission Device Based On FPGA

In aerospace and weapon engineering test tests,in order to obtain the target part status and environmental parameters of the vehicle,it is necessary to collect and monitor them in real time and do further analysis and processing.According to this application scenario,this topic addresses the flight test requirements of a flight vehicle.In order to achieve the collection of pressure sensor signals,the reception of telemetry signals,and high-speed long-distance transmission carried on aircraft,and to meet the requirements of accuracy and reliability,a multi-channel hybrid data acquisition,encoding,storage,and transmission device based on FPGA was designed and implemented.Firstly,the overall scheme design of the device is carried out according to the subject task book,and the main research contents are as follows:1.For the stability of the pressure sensor power supply,the choice and power supply output impedance mismatch EMI filter,increase filter capacitors,electromagnetic shielding design,optimization of PCB layout wiring and the choice of switching power supply with coupling inductance,to prevent the switching power supply will be ripple and noise into the pressure sensor.2.For the acquisition of atmospheric pressure parameters in each cabin of the aircraft,the acquisition system is designed in hardware with signal conditioning circuits,analogue switching circuits,anti-alias filtering circuits,voltage divider following circuits and ADC sampling quantization circuits,and in software,FPGA is used to control analog switch,ADC acquisition timing,uniform sampling,oversampling and optimization design of de extreme value and mean value to achieve high accuracy acquisition.3.For reliable storage of data,dual NAND Flash is used,and bad block management and ECC checksum are performed through FPGA-controlled Flash to enhance the reliability of data storage and data readback.4.For signal integrity before and after long distance transmission,quantitative analysis of transmission line type,signal reflection and signal attenuation was carried out,and the stability of the transmission signal was improved by adding drivers,equalisers and termination resistors.The logical design of the LVDS long line transmission link and RS422 transceiver configuration through 8b/10 b encoding and CRC verification retransmission mechanism ensures the stability of data transmission.Finally,a closed-loop ground test system was set up to carry out extensive experimental tests and data analysis on the equipment.The equipment can complete 45 channels of analogue acquisition,1 channel of PCM data and 1 channel of ultrasonic temperature measurement data reception,with acquisition accuracy within 0.2% F.S.and accuracy SFR within 0.3%,while the signal-to-noise ratio SNR is higher than 70 d B,the read-back data corresponds to the designed frame structure and the data structure is complete and error free.The LVDS-based 8b/10 b coding and CRC check retransmission mechanism is stable and feasible,enabling reliable BERfree transmission over 120 m of cable at 240Mbit/s.