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Model 2701 Service Manual Specifications A-
7
Calculating dBm characteristics accuracy
As an example of how to calculate the actual reading limits for a 13dBm measurement with
a reference impedance of 50
Ω
, assume an applied signal 0.998815V. The relationship between
voltage and dBm is as follows:
From the previous example on calculating DC characteristics accuracy, it can be shown that
a measurement of 0.998815V on the 1V range has an uncertainty of ±36.9644mV or
0.998778V to 0.998852V, using one-year specifications.
Expressing 0.998778V as dBm:
and expressing 0.998852V as dBm:
Thus, the actual reading range is 13dBm ±0.00032dBm.
dBm and dB for other voltage inputs can be calculated in exactly the same manner using
pertinent specifications, ranges, and reference impedances.
dBm
10
V
2
IN
R
REF
⁄
1mW
---------------------------
log
=
dBm
10
0.998778V
(
)
2
50
Ω
⁄
1mW
-------------------------------------------------
log
12.99968dBm
=
=
dBm
0.998852V
(
)
2
50
Ω
⁄
1mW
-------------------------------------------------
13.00032dBm
=
=
Summary of Contents for 2701
Page 15: ...1 PerformanceVerification...
Page 47: ...2 Calibration...
Page 70: ...3 RoutineMaintenance...
Page 78: ...4 Troubleshooting...
Page 97: ...5 Disassembly...
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Page 111: ...6 ReplaceableParts...
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Page 131: ...A Specifications...
Page 140: ...B CalibrationReference...