An organization called the Society for Motion Picture and Television Engineers, or SMPTE, defines methods for "motion imaging" or video and television signals. The SMPTE 310M standard was created to define the process for modulating and transmitting Motion Picture Engineer's Group, or MPEG-2 container groups or transport streams for use when television stations converted from analog to digital broadcasting.
SMPTE 310M Standards
SMPTE 310M is the method of signal modulation typically used between multiplexers, also known as data selectors – which increase the amount of data that can be sent within the network – and 8- and 16-vestigial sideband exciters used in digital transmission. VSB exciters are a critical component in monitoring and encoding the digital video and audio signal of a television station's broadcast. The transmission standard is set between 19.39 megabits per second and 38.8 mbps.
SMPTE 310M Interface Use
SMPTE 310M interfaces are typically used by television stations broadcasting digital signals under the Advanced Television System Committee standards, or ATSC, over the airwaves. Devices typically connected by this interface can help the station to monitor the video and audio signal, and conduct tests of the signal before converting it to a receivable signal by the end user. Some SMPTE 310M interfaces are built as PCI cards, while others are standalone units.
Low-Noise Environment Connection
The SMPTE 310M is meant to be used in a low-noise environment. This means there cannot be a lot of interference in the signal, so most devices are connected no less than 6 feet apart when using SMPTE 310M interface units or cards. Signal degradation or loss can occur when connecting these devices over longer distances. The MPEG-2 universal format defines the compression of the video and audio data, and an SMPTE unit or card modulates the bit rate for the transmission of the signal between devices.
The SMPTE 310M standard was originally rolled out in 1998 long before some of the equipment it would be used with was even designed. As a result, many stations with equipment designed with this standard have built systems that have frequency and timing problems with the signal modulation. Since the roll-out of all-digital broadcasting in 2009, other standards have been created that prevent the problems associated with the devices using the SMPTE 310M modulation standard.
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