This text is about tv technology. Analog (and typically digital) video indicators could also be immediately connected to subscribers’ receivers, or they may pass by means of a community termination system, corresponding to an analog or digital set-high terminal. movie mania If a sign passes by a set-top terminal, it may be demodulated, descrambled or decrypted, and remodulated—every an imperfect process.
To be able to understand how performance requirements are related, you will need to first decide all the chain from sign generation to end person. The parts of this chain will vary depending on the service, in fact. Some indicators could also be generated within the headend and even closer to the subscriber, whereas others will likely be generated hundreds of miles away. Figure 15.1 illustrates an example of the transmission elements by means of which an analog video sign could also be despatched.
The FCC’s requirements applying to cable tv systems generally specify the entire allowable sign degradation from acquisition on the headend to delivery of the ultimate signal to subscribers’ receivers (although there are exceptions). This vary of protection is shown by the second horizontal line in Determine 15.1. The standard parameters are applicable (with a couple of minor exceptions) to every analog video sign at each subscriber gear terminal beneath all normal operational circumstances.