BLOG QUESTION ADV: THE HISTORY OF FRAME RATES P. 2

1. What were two reasons why 60Hz interlaced frames chosen for over the air broadcasting? How did the introduction of color factor in?

 2. How do you convert a film to television? What is 3:2 pull down?

60 Hz was chosen for over the air broadcasting because they wanted to eliminate the intermodulation (beating distortion caused by the hum generated by an electrical current). The AC power in the United States runs at 60 Hz which results in 30 FPS. With the introduction of color, the UHF TV system needed to come up with a color system that would be compatible with black and white TVs. The system they discovered broke down the colors into Chrominance and Luminance. The 3:2 pull down is when the first frame from a film strip is captured into the Upper, Lower, and then Upper fields, the second is captured in the lower and upper field, the third is captured in the lower, upper, and lower fields, and the fourth is the upper and lower fields.