Doubt: Decoding NEC protocol from CRO display

Projects Networking, Protocols, and Devices
1

I wanted to decode the signal from an NEC protocol remote control. I use an IR Sensor (TSOP) and sent its signal to CRO. I got this image. But, unlike NEC protocol, all pulses looks inverted, why so ?

The first low pulse (which should be high actually) is of 9ms which is in agreement with NEC protocol.

The pulse following the low pulse is a high pulse (which should be low actually) is of 7.8ms, it should have been around 4ms according to NEC protocol.

Also, the address/data pulses are triangular and remain triangular at all the scale, how will I decode the ON/OFF time of these pulses ?

What is wrong with all these ?

2

Maybe the remote control doesn't use the NEC protocol? Who tells you that it does?

3

It is a remote of a NEC Projector. It is from the brand NEC

4

rishi_ar:
It is a remote of a NEC Projector. It is from the brand NEC

That doesn't necessarily mean that the remote is using the NEC protocol. It's possible that your projector is branded NEC but constructed by another company which uses another protocol.
What's the result of the decode method (auto-recognition) of IRremote (GitHub - Arduino-IRremote/Arduino-IRremote: Infrared remote library for Arduino: send and receive infrared signals with multiple protocols)?