336 Keysight N9915-90020 User’s Guide
Electromagnetic Interference (EMI) Measurements – Option 361
EMI Measurements Mode Settings
Preamplifier Control (Opt 235)
Learn more, see Chapter 9 refer to “Preamplifier Control (Opt 235)” on
page 162
.
Resolution Bandwidth (Res BW)
EMI mode has a different resolution bandwidth type for each type of EMI
measurement:
— CISPR Band Scan, CISPR Zoom Scan, and APD Statistics have of set
values of 6 dB resolution bandwidths ((i.e., 200 Hz, 9 kHz, 120 kHz), and
1 MHz impulse bandwidth). “6 dB” is displayed in the Res BW value on the
bottom left side of the display (e.g.,
Res BW (6 dB) 120 kHz).
The EMI Resolution bandwidth is auto-coupled to keep frequency range
with the selected CISPR band. If the Start or Stop frequencies are
changed, the FieldFox displays a reminder message about the CISPR band
limits.
Example of CISPR messages:
“CISPR band StartFreq limited to
30000000" and “CISPR band StopFreq limited to 300000000".
CISPR Band
a
EMI 6 dB Resolution
Bandwidth
d
CISPR Band Scan
Maximum Span
Value
b,
a
,c
CISPR Zoom Scan
Minimum Span
Value
d,e
A – (9 kHz to 150 kHz) 200 Hz 3.735 MHz 19.6 kHz
B – (150 kHz to 30 MHz) 9 kHz 168.1 MHz 882 kHz
C – (30 MHz to 300 MHz) 120 kHz 2.243 GHz 11.76 MHz
D – (300 MHz to 1 GHz) 120 kHz 2.243 GHz 11.76 MHz
E – (1 GHz to 18 GHz) 1 MHz (impulse BW) 17.6 GHz 7.895 MHz
a. The maximum spans displayed in the CISPR Band table, are only achievable when one manually couples the reso-
lution bandwidth (Res BW). Typically, the entire CISPR Band span (displayed in the first column) is used with
auto-coupled resolution bandwidth (Res BW). The CISPR Band Scan Maximum Span Values (displayed in
the third column) are actually the 75001 point limit applied to each resolution bandwidth (Res BW) when manual
coupling (Manual) is used. When manual coupling (Manual) is used, you can go outside the selected CISPR
Band.
b. The maximum number of points for a CISPR Band Scan is 75001 points.
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