Result Length Parameters (802.11n/ac/ax/be)

Menu Path: MeasSetup > IEEE 802.11n/ac/ax/be Demod Properties > Time tab

Result Length parameters specifies how much data is acquired and demodulated.

• Automatic (Default): The VSA automatically determines the measurement result length. It compares the number of symbol-times detected within the burst to the value entered in the Automatic text box and uses the smaller value as the measurement result length.

• From SIG Symbols: When From SIG Symbols is selected, the VSA uses information detected within the HT-SIG High-Throughput SIGNAL field (802.11n), or L-SIG Non-HT SIGNAL field and VHT very high throughput (VHT) physical (PHY) layer protocol data unit (PPDU):A PPDU transmitted using the TXVECTOR FORMAT parameter equal to VHT.-SIG (802.11ac), fields of the preamble to determine the Result Length.

• Manual: The VSA uses the value entered in the Manual text box as the measurement result length and ignores the number of symbol-times detected within the burst.

  The amount of data included and shown by the Time trace data display is determined from the Maximum Result Length and Manual parameters. For more information, see Time trace data.

Automatic vs. Manual Result Length modes

The following figure illustrates the differences between how Automatic and Manual modes determine the measurement result length. The table lists the measurement results lengths for Automatic and Manual modes at three different result length input settings (30, 26, and 20 symbol-times) for a burst whose pulse width is fixed at 26 symbol-times.

 

• 30 symbol time example - Burst pulse width is less than the result length settings:
  • Manual mode the VSA uses a result length of 30 and will demodulate the full 30 symbol-times even though this is 4 symbol times beyond the pulse width.
  • Automatic mode the VSA uses a result length of 26, which is the smaller value between the burst symbol-time and the Maximum Result Length.
• 20 and 26 symbol-time examples - Burst pulse width is greater than or equal to the result length settings:
  • Manual mode the VSA uses a measurement result length equal to the Manual settings, which is 20 and 26 for these examples.
  • Automatic mode uses the smaller value between the MaximumResult Length setting or the number of data symbol times detected within the burst as the measurement result length which is 20 and 26 for these examples

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See Also

Time Tab

802.11n/ac/ax/be Demod Properties