On Jan 29, 2006, at 2:03 PM, Jack Davis wrote:
Seem like someone told me that the TV electron gun operates at 60 cycles per second. Not at all sure this is right, but it MAY make a one way sweep of the screen every 1/60 of a sec. Someone else claimed the gun made a complete picture every 1/30 of a sec. That COULD mean one two way sweep. IOW, I don't know either.
It's interlaced. The odd-numbered lines are drawn on the first 60Hz pass, then the even ones on the next pass. The whole picture is therefore updated 30 times a second. The PAL system used in many countries has more lines and a frame rate of 25Hz.
I've tested shutter speeds before using a laser, a small silicon light sensor and a digital oscilloscope I borrowed from work. It worked well up to about 1/1000th where the width of the beam and the response time of the sensor start to become important.
- Dave http://www.bluemoon.net.nz/ http://www.digistar.com/~dmann/
