THE DEVELOPMENT OF COLOR TELEVISION 1956

[R_Gtx]

I've delved into my archives, and extracted the attached information sheet entitled Video Tape Recording Areas from my training notes (dated 1984). Perhaps I should now scan all my BBC television engineering training notes, 3 A4 Lever Arch files worth!!

[vk6zgo]

Incandescents are less objectionable because thermal lag in the filament reduces the amplitude of the light intensity variation dramatically.  Both show variations at twice line frequency.  But fluorescents drop intensity all the way to zero each half cycle.  So even though they are varying at roughly two octaves above most individuals cut off frequency there is sufficient amplitude to cross the detection threshold.

The television scene which shows full amplitude variation between light and dark at frame rate is highly artificial and rarely seen.  I am sure that most people would find watching such a scene disturbing, even on a high frequency monitor.

Such a transition,even at field (50Hz) rates is so rare that it is provided on TSGs as a test signal called a "bump" test,designed as a torture test for clamp circuits,dynamic range,& so on.