Though i think i have a reasonable understanding of what progressive scan is,and also what line-doubling is i'm still a little confused.For example is the Sony DRC-MF system,as opposed to so called progressive scan on other CRT televisions the same thing? Is the I-scan unit a line doubler or is it an interlace to progressive scan converter? Is progressive scan just another name for line doubling? If so what about line tripling or quadrupling? Am i right in thinking that line doubling uses some form of interpolation to 'fill in the gaps' and progressive scan simply shows all picture lines in one pass? Sorry this is a little garbled but if anyone can clarify the differences i would be very grateful.