As the number of services being distributed around the world increases, the need to monitor the MPEG transport streams being transmitted becomes ever more important.
Tektronix WebMSM monitoring software shows a geographical overview of potential problem spots, as well as providing the ability to drill down to the details of the problem.
The current trend in digital broadcast network architecture is toward a highly centralized model, with content scheduled and played out from one or more main hubs and distributed over contribution network feeds to regional or local stations. These sites are typically manned by a skeleton staff who very often do not have the time or the expertise necessary to monitor and diagnose faults in the transmission chain. In addition, transmitter sites are often completely unmanned. A centralized, Web-based monitoring solution enables the playout center or hub to monitor the entire transmission network from content generation and encoding to final modulation and transmission.
Monitoring instruments are needed that can detect impairments before they impact quality. The Tektronix MTM400 is a real-time MPEG transport stream monitor designed for use in centralized digital transmission networks. One rack unit high, it provides key measurements to ensure transport streams are error free, provides high data rate, and provides full TR101 290 monitoring of a single stream at up to 155Mb/s.
As a confidence monitor, the MTM provides the key MPEG tests. Diagnostic monitoring software options provide more in-depth analysis of the MPEG transport stream including recording capability; PSI, SI, PSIP and ARIB analysis and graphing; in-depth PCR timing analysis and graphing; bit rate testing; service logging; and service plan or template tests. Deployed at key network nodes, the system equipped as a diagnostic monitor can pinpoint the cause of faults and solve them from the central hub.
Together with WebMSM MPEG measurement manager remote control and monitoring software, the MTM400 provides a complete solution for transmission monitoring of MPEG transport streams. The WebMSM monitoring manager is an installable Java application that enables complete visibility of the error status of a transmission network from a standard Web browser. A network manager is able to build up geographical maps showing the location and status of his monitoring network, as well as mimic diagrams of the transmission network. When a fault occurs, the corresponding monitoring point is highlighted in red, enabling the network manager to drill down to the individual monitor and determine the nature of the fault. The management software can be used to manage a mixed network of confidence and diagnostic monitors.
However, simply monitoring the syntax of an MPEG transport stream according to test standards is not enough to guarantee that the correct information is being delivered to the viewer’s receiver. Ensuring that the contents of the transport stream are correct requires the monitoring equipment to have prior knowledge of what the broadcaster plans to transmit. A method of achieving this is to enable the broadcaster to identify a small number of key parameters that can be used to verify the contents of the transport stream.
These parameters form a service plan template. The monitoring equipment extracts the actual values from the transport stream and compares them against this template, indicating when a discrepancy occurs. This user-defined checking option enables verification that the correct content is being transmitted.
Mark Barnes is an MPEG product manager at Tektronix.
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