Sony FD Trinitron WEGA KV-36XBR800 Operating Instructions Manual page 51

Changing the
Picture Size
The zoom feature lets you vary the relative size of the left and right
pictures.
1 Move the joystick ÷ or ÷ to
activate the picture that you
want to resize.
2 Move the joystick _ to enlarge
the picture.
3 Move the joystick _ to make the
picture smallen
When you adjust the picture sizes, the TV memorizes the change. The
next time you use the Twin View function, the memorized sizes
appear.