Keysight X Series Measurement Manual page 61

Concepts
MSR Measurement Concepts
In the MSR Total power is the sum of carrier powers which are calculated by
the integration power of the specified bandwidth with the specified weight.
Total power is available only when powers of all the carriers with Measure
Carrier On are calculated.
This measurement requires the user to specify measurement bandwidths of the
carrier channel and each of the offset/region frequency pairs up to 12 (A - L).
Each pair may be defined with unique measurement bandwidths. The results
are displayed both as relative power in dBc, and as absolute power in dBm. The
measurement supports the limit preset as described in "Offset/Limit Presets"
on page 67.
Keysight N9083A & W9083A Measurement Guide 61