After you leave the subscriber s house, something changes just a little, and the picture goes away. You can use the attenuator trick here, too, but you may need to get more sophisticated to really figure out what is going on. Next We re going to spend the rest of the year on some of the fundamentals of the industry that I haven t seen covered recently. The material in this explanation is adapted from Chapter 8 of Ciciora et. Image Rejection Basics Image rejection is a parameter that has plagued the cable TV industry for a long time, and just won t go away.
Image problems look much like distortion, but are caused by entirely different mechanisms.
If you treat the problem as if it was distortion, you will not solve it. One of the most fundamental test tools we have, and one of the most effective, is a simple 6 dB attenuator. Combined with a good set of eyes, this tool can tell you a whole lot about where problems come from. All rights reserved.