Academic literature on the topic 'Modems ADSL'

Automatic Dependent Surveillance Broadcast (ADS-B) is envisioned to support seamless aircraft surveillance and enhanced air-to-air and air-to-ground applications. ADS-B is an integrated system, dependent on on board navigation systems to obtain aircraft state information as well as a communication data link to broadcast this information to Air Traffic Control (ATC) on the ground and other ADS-B equipped aircraft. To quantify system safety, a good understanding of the potential failure modes of the system is vital. ADS-B system failure modes include those from the communication and navigation systems and human and environmental factors, as well as ADS-B-specific components. In this paper, potential failure modes of the ADS-B system are identified using an approach developed in this paper. The end output of the approach is an ADS-B failure mode register. However, the approach is transferable to other ATC surveillance systems. The paper further provides the failure classification and modelling, and also analyses the failure modes' impact on ATC operations and finally proposes potential mitigations. It is important to note that the work carried out in this paper is based on the assumption that the ADS-B operates as the primary surveillance source for the ATC.

The requirement for an automated test system has immensely increased due to the realization that manual testing is associated with additional resources and staffing constraints. In order to achieve a competitive edge, reduced development cost, timely product delivery, and product quality are mandatory in today's organization. Manual testing requires skilled operators that increase cost, time, and product delivery. The low cost computer-based automated system helps to get an edge by fulfilling these organizational demands. In this paper, an automated testing system has been developed to support functional testing of all phases of Nortel Networks 1-Meg modem system as its system under test (SUT). The modem is an inherently complex asymmetric digital subscriber line (ADSL) product and its testing is far more complex than just verification of process faults. The complexity of ADSL system renders automated test system an important and imperative part of ADSL testing. The subject paper demonstrates the indispensable need of automated test system for ADSL testing and its relative advantages in providing some benefit for the organization.