B&K Precision 2658A - Manual - Manual (Page 32)

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* If the unit is changed to
dBμV, dBmV, dBV or dBm, the offset is automatically changed.
2. By pushing , the step size of offset is changed. (10 dB, 1 dB, 0.1 dB)
9.6 Setting of Input Impedance
By pushing , the input compensation can be set to 50
Ω (no offset) or 75 Ω. (5.6 dB offset
compensation)
The reference level is adjusted automatically, based on the input impedance selection. When the input impedance
is set to 75
Ω, the reference level is displayed including offset and conversion of 75Ω. For the amplitude reading to
be correct, a coaxial
50 Ω /75 Ω impedance conversion adapter must be connected to the RF input.
* When “75
Ω” is selected, values in Amplitude axis setting values display area will change according to
75
Ω, and the offset is set to 5.7 dB (insertion loss of 50 Ω /75 Ω adapter ). Moreover, the offset can be
changed.
When the unit at marker point is set to W, V, V/m or other, it is converted correctly from dBm.
* Be sure to attach a coaxial
50 Ω /75 Ω impedance conversion adapter when selecting “75 Ω”
9.7 Reference Level Setting Range for Each Unit
Unit dBm
dBμV
dBmV dBV
Maximum 10 117 57 -3
Minimum -40 67 7 -53
Minimum
(shifted spectrum data)
-60 47 -13 -73
“Available unit in measuring function”
Unit
dBμV/m (Electric field strength measurement)
dBμA/m
(Magnetic field strength
measurement)
Setting M401 M402 M403 M404 M405 M406 CP-2S
Maximum 143 146 149 150 137 159 160 ~ 203
Minimum 93 96 99 100 87 109 110 ~ 153
Minimum
(shifted spectrum
data)
73 76 79 80 67 89 90 ~ 133
* When the reference level is set between “Minimum” and “Minimum (shifted spectrum data)”, the
spectrum of “Minimum” is shifted and displayed on the screen.
F3
F6