There is nothing special needed Harrison!
When you look at the back of your 1084S(or just a 1084) you will see, that everything is already there!
This Monitor Type also operates at 50/60Hz (that is why PAL and NTSC Consoles work with this nice old Monitor)
When some old games needs 15Hz(or 15Frames per Second for that matter) you can just adjust the framelimit to that value, to get the desired framerate.
I also use this Monitor for my Mame machine (which is also connected sometimes to this Monitor - just for the retro effect ) and getting correct speeds is often vital, but you don`t need a special monitor. I think the most emulators are fine in regard of speed and frame options nowadays.

I will post pictures of my old 1084S hooked up to my little archos. i just need one more post to post the links
PS isn`t it wonderful that this old antiquated hardware still works fine after all these years? What else works so good after all this years? Even my old Amiga 500 still works! Which is amazing. My old 286 frome the same time died long ago....