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signal. Crest factor is the ratio of a signal's peak value to its RMS value and varies according to waveshape. The table
below shows several common waveforms with their respective crest factors and RMS values.
If an average-reading voltmeter is used to measure the "DC voltage" of a waveform, the reading may not agree with
the DC Offset setting. This is because the waveform may have a non-zero average value that would be added to the
DC Offset.
You may occasionally see AC levels specified in "decibels relative to 1 milliwatt" (dBm). Since dBm represents a
power level, you need to know the signal's RMS voltage and the load resistance in order to make the calculation.
dBm = 10 x log
(P / 0.001) where P = VRMS
10
For a sine wave into a 50 Ω load, the following table relates dBm to voltage.
dBm
+23.98 dBm
+13.01 dBm
+10.00 dBm
+6.99 dBm
3.98 dBm
0.00 dBm
-6.99 dBm
-10.00 dBm
-16.02 dBm
-30.00 dBm
-36.02 dBm
-50.00 dBm
-56.02 dBm
For 75 Ω or 600 Ω loads, use the following conversions:
dBm (75 Ω) = dBm (50 Ω) – 1.76
Keysight EDU33210 Series User's Guide
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RMS Voltage
3.54 Vrms
1.00 Vrms
707 mVrms
500 mVrms
354 mVrms
224 mVrms
100 mVrms
70.7 mVrms
35.4 mVrms
7.07 mVrms
3.54 mVrms
0.707 mVrms
0.354 mVrms
Peak-to-Peak Voltage
10.00 Vpp
2.828 Vpp
2.000 Vpp
1.414 Vpp
1.000 Vpp
6 32 mVpp
283 mVpp
200 mVpp
100 mVpp
20.0 mVp
10.0 mVpp
2.00 mVpp
1.00 mVpp
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