|MadSci Network: Physics|
Hello Shubha: What you see in the flicker is called aliasing. This phenomenon is common to all sampling systems (non-continuous). The way pictures are displayed on the cathode ray tube (both computer and television) is by either a single beam (black and white) or triple red_blue_green beams (color) painting lines left to right and up to down at given time intervals. Some instances use "interlacing" meaning the lines are drawn with one-line gaps at a time and blank files filled-in before the next update. One thing is, if the scans and scan rates aren't synchronized the picture of the picture shows a lot of distortion to the point that information is indiscernible. Aliasing is also evident in movies in the case of rotating spoke wheels. Depending on the velocity of the wheels, they sometimes reverse the rotation. Instrumentation engineers use sample data systems in many applications. To ensure validity of the data, either pre-sample filters or over-sampling speeds must be used. Here are some Internet sites you may find helpful: www2.cs.ust.hk/faculty/layers/comp342/waveforms/waveforms.html www.hallresearch.com/hall/Brochures-pdf/vtv-4.pdf www.ee.washington.edu/conselec/CE/kuhn/ntsc/95x4.htm members.aol.com/ajaynejr/vidres.htm Your MAD.SCI Micro
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