OBW Summary Table (Markers)

The OBW Occupied bandwidth is closely related to channel power. It indicates how much frequency spectrum is covered by some given percentage (often 99%) of the total power of the modulated signal. marker function provides an OBW Summary table which contains results that are derived from the OBW marker on the corresponding trace. There is an OBW Summary table available for each OBW Marker.

The OBW Summary table will only contain data when the OBW marker is enabled for the corresponding trace and that trace contains spectrum data.

To show the OBW Summary Table

To show the OBW Summary table, select the OBW Summary table that corresponds to a trace with the OBW marker enabled. For example, if the OBW marker of interest was shown in Trace D, activate any of the other trace windows and click Trace > Data > Marker > Trace D > OBW Summary.

To learn how to use the OBW Marker, see Making an OBW/BW Measurement.

Averaging

The OBW Summary table always shows OBW results calculated from the data shown in the spectrum trace containing the OBW marker.

Averaged OBW results can be obtained by enabling averaging and placing the OBW marker on an averaged Spectrum trace. When this is done, the OBW Summary table will show values calculated from the averaged trace.

Data Results

The OBW Summary table provides both OBW and BW data results (to learn about how OBW data results are computed, see the Measurement Algorithm section of the About OBW Marker topic):

Occupied Bandwidth

Occupied Bandwidth [Hz]: bandwidth containing the specified % Power
Power [dBm deciBels referenced to a milliWatt: dB relative to 1 milliwatt dissipated in the nominal input impedance of the analyzer]: measured power in the occupied bandwidth
Total Power [dBm]: total power in the measurement span
Power Ratio [%]: ratio of the power in the occupied bandwidth to the Total Power, which is equal to the % Power parameter
Upper Freq [Hz]: the occupied bandwidth's upper frequency
Lower Freq [Hz]: the occupied bandwidth's lower frequency
Centroid Freq [Hz]: the midpoint frequency of the OBW
Offset Freq [Hz]: the difference between the VSA's center frequency and the OBW centroid frequency

X dB Bandwidth

X dB Bandwidth [Hz]: calculated X dB bandwidth
Bandwidth Threshold [dB]: threshold used in calculating the X dB bandwidth, which is specified by the X dB Bandwidth Threshold parameter
Lower Freq [Hz]: the X dB bandwidth's lower frequency
Upper Freq [Hz]: the X dB bandwidth's upper frequency

Querying summary table data results programmatically

To programmatically query the Trace Summary Table data results using the Summary() and SummaryUnit() methods in the MeasurementData object.

See the How To Query Summary Table Data Results topic for more information.