Same here throbs, never twice the same colour isnt what it stands for, I think (about to be corrected) it stands for national televison system comittee,
I thought 'standards' rather than 'system'?.
they also said at college pal stands for perfect at last.
Pal contains a colourbust signal that calibrates the colour line by line, ntsc doesnt do that and on old tellys the colour went squiffy to the right of the screen and had to be adjusted every so often.
Both contain colour bursts - and PAL is just a simple improvement on NTSC (they are very similar otherwise).
PAL stands for Phase Alternating Line - the problem with NTSC is that the specific colour is dependent on the PHASE of the signal, so if the phase changes, then the colour does as well (this is why NTSC TV's had Tint controls - to make the colour something like correct - and PAL sets didn't, as there was no need). Essentially PAL sends each alternate line of colour inverted, this is passed through a 64uS delay line and 'mixed' with the previous line this cancels out any phase errors, ensuring correct colours irrespective of phase errors.
America was stuck with a poor system because they 'did it first' (rather like the UK with 405
), the technology for PAL probably didn't exist when NTSC was designed, and of course they didn't have a few years of 'beta testing' to fall back on, as Telefunken did with NTSC being the 'beta test'
The volatge in the uk at one time differed as to where you were in the country, most of my valve radios have multiple taps for the mains power.
Some say 50hz was a trade off from a diesel engines max efficiency (which is normally 2200 rpm rather than 3000 req for 50hz), and some say its an efficient speed to run a turbine.
The Wikipedia article linked above seems quite helpful - and of course many radios and TV's were AC/DC as well as multi-voltage, because some mains was DC.
Not far from me there was a private mains system (until 'relatively' recently), where a local large company (Staveley Works) provided power for much of the town is was part of, at 25Hz or so I believe?.