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An Overview of Digital Video Recorders
Published in Jimmy Schaeffler, Digital Video Recorders, 2013
Once also called a personal video recorder (PVR), but now known almost exclusively among aficionados and most laypeople as simply a digital video recorder (DVR), the DVR device is essentially an in-home computer. In its typical forms, the DVR is either its own standalone set-top box (that only functions as a DVR) or is part of a cable, satellite, or telephone3 company's set-top box. This would be the set-top box that sits beside, below, or on top of a TV and also permits access to that company's multichannel content. The DVR contains a mechanism—called a hard drive—onto which the live, real-time audio and video digital content is recorded. This content is then delivered to the TV (or similar) screen upon command by the user.4 In other words, instead of saving documents or files like a personal computer (PC) does, the DVR saves the actual digital video and audio signal that arrives at the DVR and the monitor(s) it serves. This digital content is recorded, of course, back onto the hard drive for later manipulation by the DVR user.
Fault Ride-Through Capability Improvement of Grid Connected PV System Using Dynamic Voltage Restorer
Published in Electric Power Components and Systems, 2020
Ahmed AbuHussein, Mohammad Ashraf Hossain Sadi
This paper proposes the DVR to enhance grid integrated PV system behavior during faults, to maintain continuous operation of the PV system components, and to protect the power electronics converters from system disturbances. The DVR performance was when compared with the SDBR. Based on simulation results, the following points are noteworthy.The DVR is a very effective means to improve the FRT capability and to keep up with the strict grid code of PV systems.The power electronics converters are well protected by using the DVR.The need to disconnect PV Plants from the grid can be mitigated by the use of the DVR, and a continuous supply of power is available.The DVR injects fewer harmonics than the SDBR into the system.The DVR ability to absorb more energy than the SDBR and to reduce severe currents fed to 3LG fault will help reduce the size of PDs.The DVR reactive power control capability relieves the inverter from reactive current stress during fault and reduces the size of the inverter as well; hence, the cost is reduced.