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(From: Tony Duell (ard@p850ug1.demon.co.uk).)
Although this very old Sony set (KV-1300) receives PAL signals, it's much closer to an NTSC set inside. In fact it's one of the strangest PAL decoders that I have ever seen. As you know, in the PAL system, the phase of one of the colour signals is inverted on each line, and in the receiver there's a bistable which switches at half the line rate to re-invert the colour signal on alternate lines. Well, to avoid a patent, the Sony set only uses (say) the in-phase colour signal that's received on alternate lines. For the lines in between it uses the previous line's colour signal (ignoring the incoming inverted one), which has been stored in a delay line.
This approach avoids the main patent on the PAL system. It also means that this set doesn't automatically correct for phase errors in the colour signals - it's almost an NTSC decoder. Hence the hue control (which is also on my kV1320UB schematic). It's just about the only set like that.