34 34405A User’s and Service Guide
2Features and Functions
You can view and select the R
REF
value in the secondary
display as described in “Editing Values in the Secondary
Display” on page 45.
dB
When enabled, the dB operation computes the dBm value for
the next reading, stores the dBm result into the dB Ref
register and immediately produces the following calculation.
The first displayed reading is always precisely 000.00 dB.
dB = 10 x Log
10
[ (Reading
2
/ R
REF
) / 0.001W ] - dB Ref
• You can set dB Ref to any value between 0 dBm and
\
120.0000 dBm. The default R
REF
is 0 dBm.
• Numeric results are displayed in the range of ± 120.000
dB with 0.01 dB resolution shown, independent of the
number of digits setting.
You can view and edit the dB Ref Value in the secondary
display as described in “Editing Values in the Secondary
Display” on page 45. The dB Ref value is displayed on the
secondary display in the range of ± 120.000 dBm with 0.001
dBm resolution shown.
Min/Max
The Min/Max (Minimum/Maximum) operation stores the
minimum and maximum values, the average, and the number
of readings during a series of measurements.
When enabled, the Min/Max operation turns on the MnMx
annunciator and begins accumulating various statistics about
the readings being displayed.
dB
Null
Null
Shift
MnMx
34405A users guide.book Page 34 Saturday, September 2, 2006 3:38 PM