English NTSC TV's.

[NewVista]

So the sneaky Sony TV would store the 'NTSC' lines and repeat them in place if the sequential 'PAL' lines

A standard PAL-D TV would store the 'NTSC' line and process it with subsequent 'PAL' line. This would halve the chroma vertical resolution.

But it gets worse because of interlaced scanning: now sampled detail from two lines above is added to 'PAL' line
creating more degradation than unprocessed pure 'PAL' & 'NTSC' lines (as in a PAL-S receiver)?
And if there is picture motion even more blur.