Complex sentence: France required a slightly modified version of the machine to match the positive video modulation of SECAM sets while the USA and Canada required a different ULA chip and modulator to cope with their 525-line VHF (NTSC) television systems.
Split into simpler sentences: France required a slightly modified version of the machine to match the positive video modulation of their sets. The USA and Canada required a different ULA chip and modulator to cope with their 525-line VHF television systems.