Preamble Type (MB-OFDM)

Menu Path: MeasSetup > MB-OFDM Demod Properties > Format tab

Default: Auto (See MB-OFDM Standard Setups/Presets Table.)

Range:Standard, Burst, or Auto

Preamble Type specifies either a single preamble type for the signal (Standard or Burst) or enables autodetection of the preamble type for each measurement. The Standard Preamble consists of (24) Packet/Frame Sync symbol-times and (6) Channel Estimation symbol-times for a total of (30) symbol-times, while the Burst Preamble consists of (12) Packet/Frame Sync and (6) Channel Estimation symbol-times for a total of (18) symbol-times. To learn more, see MB-OFDM Packet.

For Data Rates of 53.3, 80, 106.7, 160.0 and 200.0Mb/sec, packets use the Standard Preamble; for Data Rates of 320.0, 400.0 and 480Mb/sec, the first packet uses the Standard Preamble, after which the remaining packets may use either the Standard Preamble or the Burst Preamble, in which case the preamble type is coded in the Header for the next packet. Typically, use the Burst Preamble in a streaming mode, where a burst of packets is transmitted with only a minimum inter-frame separation time. While selecting a Burst Preamble for a data rate of 200.0Mb/sec or less is not to specification, the VSA allows this setting for special cases.

The Auto setting can be used when a signal contains one or both preamble types. The detected preamble type is displayed in the Det Pmbl Type data value in the MB-OFDM Composite Error Summary Table.