7451A/7461A/7461P Digital Multimeter Operation Manual
5.9.4 dB and dBm calculation
5-37
5.9.4
dB and dBm calculation
1. Function
The dB calculation, in which the decibel conversion is performed, can be performed only in the volt-
age and current measurements.
The dBm calculation, which is useful to calculate the power gain per 1 mV, can be performed only in
the voltage measurement.
If the zero is measured while the dB and dBm calculations are performed, the calculation error occurs
and error message is displayed.
Only one calculation can be selected from the dB, dBm, and scaling calculations at a time.
The dB and dBm calculation equations are shown below.
When dB or dBm is selected from the MATH item in
, the MATH lamp in the display sec-
tion turns on.
CAUTION:
The actual measurement value is not displayed while the dB or dBm calculation is performed.
Remember that any hazardous voltage present on the input connector or test lead may not be
detected at this time.
dB: Display = 20 log
10
| Measurement value |
Constant D
dBm: Display = 10 log
10
(Measurement value)
2
/ Constant D
10
-3
MENU
MENU
..3.. CALC
MATH
OFF/dB/dBm/SCL
