As we all know, CIR data under the NLOS environment should be more difficult to identify the first path. Why do I stack CIR data measured in the Los environment and cir data measured in the NLOS environment have little difference? Is the data I read true or processed by dacwave?
What is your environment? For both of them you have a very strong signal and virtually no reflections so my guess would be fairly short range and in an open field.
It looks like your NLOS signal is very slightly weaker and has a few more reflections but not a lot. What did you use to block the line of sight?
It depends what your partition is made of. Cloth, plastic, plasterboard or even thin sheets of wood have very little impact while a thin layer of metal will have a huge effect.
Water is also a very effective at blocking the signal so standing in between the antennas is a rude but effective way to block the direct signal.
Also your CIR data has negative values which implies you are only looking at one part of it. The output gives both real and imaginary data, looking at the magnitude of the two combined (sqrt(real^2 + imag^2)) will give you a better view of total signal power.
It’s an approximation in order to run on lower end hardware.
Few embedded microcontrollers have hardware support for floating point maths, this means that it will take several hundred clock cycles to perform an accurate square root calculation.
In this situation the exact number isn’t too critical and so the speed / accuracy trade off of the approximation is worth it.
If you are running on a PC or something with a hardware FPU (or don’t care about speed) then ignore this approximation and use the true square root.