B&K Precision 5492BGPIB - Manual - Manual (Page 34)

Basic Measurements
34
down arrow keys can be used to move the decimal place left or right of its current position.
4. Press (ENTER) to confirm the reference value, “CHANGE SAVED” will be displayed for a
moment, and the multimeter will return to the submenu level. Press (ESC) to cancel the
reference value input, and the multimeter will go back to the submenu level without changing the
reference value.
5. Press → key to exit the menu and return to the percent math operation.
The multimeter will display measurement result of the percent calculation. If the value of “Input” is larger
than that of “Reference”, displayed result will be positive. Contrarily, it will be negative if the value of
“Input” is smaller than that of “Reference”.
3.8.3 dB Calculation
The 5492B can express AC and DC voltages in dB units. The relationship between dB and voltage is
defined by the following equation:
dB = 20 log
VIN
VREF
Where: V
IN
is the DC or AC input signal
V
REF
is the specified voltage reference level
The instrument will read 0dB when the reference voltage level is applied to the input.
If a relative value is in effect when dB is selected, this relative value will be converted to dB value before
REL is applied. If REL is applied after dB function has been selected, dB reading will have REL applied
to it directly.
To set the reference voltage, perform the following steps:
1. Press + for dB math operation and the reference value is displayed:
REF: +0.00000
2. Use and keys to select cursor position and use and keys to increment
or decrement the digits respectively. Enter a value.
3. Press (ENTER) to confirm the reference voltage, and the message “CHANGE SAVED” will be
displayed for a moment. The multimeter will then return back to the measurement status.
4. Now the multimeter will display the result of the dB calculation.
If you want to change the parameter values when dB function is in effect, you can do the following:
1. Press → to enter the command level, “4: dB REF“ will be displayed.
2. Press to enter the parameter level, and the reference value will be displayed:
REF: +1.00000 .
3. Use and keys to select cursor position and use and keys to increment
or decrement the digits respectively. Enter a value and units prefix.
4. Press (ENTER) to confirm the reference value, the message “CHANGE SAVED” will be
displayed for a moment, and the multimeter will return to the submenu level. Press (ESC) to
cancel the reference value input, and the multimeter will return back to the submenu level without