HP WaterSkis E1412A, WaterSkis E1312A manual DBm Measurements, Storing the dB Reference Value

Storing the dB

Reference Value

dBm Measurements

Storing the dBm

Reference Resistance

Value

Do not confuse this operation with the dBm reference (DBM) function. See the next section, “dBm Measurements”, and take note of the multimeter's reference resistance setting (dB uses a reference level, dBm uses a reference resistance).

•The dB reference value is stored in the multimeter’s dB Relative Register. You can enter a specific number into the register using the CALCulate:DB:REFerence <value> command. Any previously stored value is replaced with the new value. Use the following commands to activate the dBm function and input a reference value. The calculate state must be enabled before you can store a value in the dB Relative Register.

CALCulate:FUNCtion DB	Set math function to DB.
CALCulate:STATe ON	Enable math operation.

CALCulate:DB:REFerence <value> Store a dB reference value.

The dBm operation calculates the power delivered to a resistance referenced to 1 milliwatt.

reading2

dBm = 10 × log -----------------------------------------------------------------------------------

10 (reference resistance) × (1 mW)

• Applies to dc voltage and ac voltage measurements only.

• You can choose from 17 different reference resistance values. The factory setting for the reference resistance is 600 Ω. Set your desired value with the CALC:DBM:REF <value> command.

The choices for <value> are: 50, 75, 93, 110, 124, 125, 135, 150, 250, 300, 500, 600, 800, 900, 1000, 1200, or 8000 ohms.

• The reference resistance is stored in nonvolatile memory, and does not change when power is removed or after the multimeter is reset.

Do not confuse this operation with the dB reference (DB) function. See the previous section, “dB Measurements”, and take note of the multimeter's dB reference setting (dB uses a reference level, dBm uses a reference resistance).

•Use the following commands to activate the dBm function and input a reference resistance value. The calculate state must be enabled before you can store a value in the Reference Resistance Register.

CALCulate:FUNCtion DBm	Set math function to DBm.
CALCulate:STATe ON	Enable math operation.

CALCulate:DBM:REFerence <value> Store a dBm reference.

Chapter 2 HP E1312A/E1412A Multimeter Application Information 43