Use FPGA to Filter Wave in PC Board Reverse Engineering
Use FPGA to Filter Wave & Anti-Interference in PC Board Reverse Engineering
The main function of Use FPGA to Filter Wave in PC Board Reverse Engineering is to resist shock waves and mosquito interference, and turn the effective projectile signal into a signal with a pulse width of 50 μs, then output to the lower processing circuit. The chip used in the design is the EPM7128SLC84-15 and MAX7000 series. The following is a detailed introduction on how to implement filtering and anti-interference:
resist shock wave pcb circuitry diagram
When an object passes through the light curtain, the pulse width of the generated square wave is: T = (L + D) / V. Where L is the length of the flying object, D is the thickness of the light curtain surface, and V is the velocity of the flying object. The shock wave is calculated by the speed of sound.
Use FPGA to Filter Wave & Anti-Interference in PC Board Reverse Engineering
When V is 340m/s and D=3mm, it can be seen that the pulse width of the square wave signal generated by the shock wave passing through the light curtain is: T1=D/V≌8.8μs; if V=330m/s, then T1≌ 9.1 μs. The flight speed V of mosquitoes and other flying objects is 20m/s, and the length L of the object is about 10mm.
It can be seen that the square wave signal pulse width generated by mosquitoes flying over the light curtain is T2≌650μs. The infrared-intensity vertical target test system test projectile velocity range is 200-1200m/s, mainly used for 5.8mm, 7.62mm, 9mm three kinds of bombs;
the impact of shock waves is mainly caused by the measurement of 9mm × 19mm pistol bullets, The projectile velocity is about 320m/s. According to the bullet speed and the length of the bullet, it can be seen that the square wave signal pulse width generated by the projectile passing through the light curtain is in the range of T3=37.5 μs.
resist mosquito interference circuitry board diagram