Active Channel Detection (1xEV-DO)

Default: Cleared (See 1xEV-DO Standard Setups/Presets Table.)

Active Channel Detection parameters allow control of what 1XEV-DO channel data is included in the composite trace data results. The available channel data and detection modes are dependent upon the signal link Direction as described in the following sections.

ForwardLink Direction signals

Allows you to specify the detection mode for the following forward link "Predefined Active Channel" data channel:

Predefined Active Channel

Data W16(0:15) - Forward Traffic Data channel, code layer 16, code channels 0 through 16

Selected: Forces the VSA to include all Data channel data in the composite trace data results.

Cleared: The VSA uses auto detect mode to determine the active "Data" code channels. Only data from the active code channels are included in the composite trace data results.

ReverseLink Direction signals

For reverse link direction signals, depending upon the selected Detection Mode, the following "Predefined Active Channel" forward direction TDM time division multiplexing burst: A contiguous portion of a TDM data stream using PHY parameters, determined by the Downlink Interval Usage Code (DIUC), that remain constant for the duration of the burst. TDM bursts are not separated by gaps or preambles. channels may or may not be included in the composite trace data results:

Predefined Active Channels

W4(2): Q - Data channel for code layer 4, code channel 2.

ACK Acknowledgement W8(4): I - Acknowledgement channel, code layer 8, code channel 4, the I branch.

DRC W16(8): Q - Data Request Channel, code layer 16, code channel 8, the Q branch.

Pilot W16(0): I - Pilot channel, code layer 16, code channel 0, the I branch

Detection Mode

Auto option
The VSA uses auto-detect mode to determine which of the available "Predefined Active Channel" channels are included in the composite trace data results. The "Predefined Active Channel" selections are not available in Auto mode.
Semi-Auto option
Cleared - Predefined Active Channel check boxes
The VSA uses auto detect mode to determine which cleared Data, ACK, DRC or Pilot channel data is included in the composite trace data results.
Selected - Predefined Active Channel check boxes
Forces the VSA to include the selected Data, ACK, DRC or Pilot channel data in the composite trace data results.
Predefined option
Cleared - Predefined Active Channel check boxes
The VSA does not include the cleared Data, ACK, DRC or Pilot channel data in the composite trace data results.
Selected - Predefined Active Channel check boxes
Forces the VSA to include the selected Data, ACK, DRC or Pilot channel data in the composite trace data results.

This feature can be used to troubleshoot a problem in the forward link Data channel. For example, if a Data channel is supposed to be active but cannot be detected by the VSA, the Composite EVM Error vector magnitude (EVM): A quality metric in digital communication systems. See the EVM metric in the Error Summary Table topic in each demodulator for more information on how EVM is calculated for that modulation format. result will appear better than it actually is. To include the missing data channel, select Data W16 (0:15) and all Data channels will be included in the Composite EVM measurement result.