I think I know this guy since it's me... haha
When I did that it reminded me of a aim 9 growl I heard on DCS ( this was a while ago, lock-on or FC era )
I'm not a fighter pilot, but I have studied aircraft systems engineering, and I've been working on EC665 Tigre and NH90 transport helicopters for some years. I'm kind of a nerd, so i've searched how those tone worked based on pictures, and technical papers.
That's where i found the pitch up on lock was not realistic. For old gen seakers, there may not be a pitch variation. Sure the technical papers doesn't go into detail on that specific main "carrier" frequency behaviour, so i may be wrong.
Recent DCS plane modules doesn't get this weird tone so i think they found out this wasn't realistic ( or popular among seker systems). As far as I remember, the seekers were later "digitalized" so the tone was computed insted of directly a seeker feedback signal.
It's quite easy to simulate a rotating obturator on a AM modulator. You just have to get the obturator pattern + the rotation speed. You just multiply this pattern with a square carrier, and you get a "off center" tone
You just have to modify the multiplicative coefficient to simulate the target coming to the center. ( locked sound )
This is OK for very old seekers, but later they added Frequency modulation for better angular precisiob, so the sound would be somewhat different
That's also quite easy to simulate with a FM modulation. This doesn't mean a pitch up on lock, but a different tone overall.
Another more complex but realistic way to do this is to use free programs such as Blender, with LuxCore Render to simulate the optical signal, then use some python scripts to transform the sensor images into an audio signal.
BTW, the only people that can precisely tell what they should sound like are those who had them in their hands, because we still can't tell what processing have been done to the raw signal before it gets to the headset.
Edit: Heres a small experiment without lenses to illustrate what i meant :
nonoise0001-0128.mp4
EDIT2: Heres the result ...
Edit 3: My bad, wrong pic
So if anyone has the correct info on the sun disks etc... I could try to recreate it.