Sharpness controls have been around since the 50's.
" Noise" is mostly on the high freq side of the video.
All the control does is cut off some of hi freq video.
If you have a perfect signal & TV you can run it
full sharpness. If a grainy pix turn it down. You will
loose small detail but the pix will be better.
The peak pix control is the same on newer Zeniths.
Zenith used the control on almost all its sets except
the small B&W's.
73 Zeno
LFOD !