5Key Reference
114 N9342C/43C/44C User’s Guide
OBW calculation. The x dB bandwidth result is also 
called the emissions bandwidth (EBW). This sets 
the green frame (f1 and f2 are the two cross points 
of the signal and the pair of vertical lines of the 
displayed green frame) to your specified dB value 
below the maximum power, and compute the total 
power in the frame. The emission bandwidth is 
then calculated ranging from 0.1 dB to 100 dB (the 
default value is set to 26 dB).
ACPR
The adjacent channel power ratio (ACPR) measures 
the power ratio between the main channel power 
and the adjacent channel power.
ACPR measures the total power (RMS voltage) in 
the specified channel. The measurement result 
reports the ratios of the two adjacent channel 
powers to the main channel power.
Center Frequency
Key access: [MEAS] > {ACPR} > {Center Freq}
Sets the center frequency of the main channel 
power.
Main Channel
Key access: [MEAS] > {ACPR} > {Main Channel}
Specifies
  the  range  of  integration  used  in 
calculating the power in the main channel. Use the 
knob, the arrow
  keys, or  the  numeric  keypad  to  set 
the bandwidth.
Adjacent Channel
Key access: [MEAS] > {ACPR} > {Adj Channel}
Specifies the range of integration used in 
calculating the power in the adjacent channel. Use 
the knob, the arrow keys, or the numeric keypad to 
set the bandwidth.