8060A
Instruction Manual
3-8
For an example of how to use this feature, let’s assume that you want to
make ac voltage dBm measurements referenced to 50
Ω
. First select the
8060A ac voltage dB function and the 2V range. Referring to Table 3-1, we
find that the equivalent voltage level for 0 dBm for 50
Ω
is 0.2236V and the
equivalent dB level for 0 dBm referenced to 600
Ω
is -10.79 dBm. Apply an
ac voltage to the 8060A input (V
Ω
S and COMMON) and adjust the applied
voltage level until the 8060A displays -10.79. Now press the REL button.
The display should read 0.00 (with the dB and REL indicators at the top of
the display). Measurements taken with the ac voltage dB function will now
read dBm referenced to 50
Ω
.
Table 3-1. Equivalent Voltage Levels for Modifying the Reference
Impedance
Reference
Impedance Z (
Ω
)
Equiv. Voltage
Level
Equiv. dB Level for 0
dBm REF. to 600
Ω
as Shown on the
8060A Display (dBm)
50
75
90
125
150
300
600 (power-on value)
900
1000 (dBV)
For
0 dBm (V)
0.2236
0.2739
0.3000
0.3536
0.3873
0.5477
0.7746
0.9487
1.0000
-10.79
-9.03
-8.23
-6.81
-6.02
-3.01
0.00
1.76
2.22
2
4
8
16
For
0 dBm (V)
1.4142
2.000
2.828
4.000
5.23
8.24
11.26
14.26
Use the following formulas to calculate equivalent voltage levels for
reference impedances not listed.
For dBm: 0 dBm level (V) =
.001xdesired ref.impedance( )Ω
600Ω Ref. Equiv. (dBm) = 20 log [0 dBm level (V)/.7746]
For dBw: 0 dBw level (V) = desired ref.impedance( )Ω
600Ω Ref. Equiv. (dBm) = 20 log [0 dBm level (V)/.7746]
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