 As a result, this system supplanted John Logie Baird's 240 line mechanical progressive scan system that was also being trialled at the time.From the 1940s onward, improvements in technology allowed the US and the rest of Europe to adopt systems using progressively higher line-scan frequencies and more radio signal bandwidth to produce higher line counts at the same frame rate, thus achieving better picture quality.However the fundamentals of interlaced scanning were at the heart of all of these systems.