Preamplifier Control (Opt 235); Resolution Bandwidth (Res Bw) - Keysight A Series User Manual

Electromagnetic Interference (EMI) Measurements – Option 361
EMI Measurements Mode Settings

Preamplifier Control (Opt 235)

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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
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".
a
CISPR Band
A – (9 Hz to 150 kHz)
B – (150 kHz to 30 MHz)
C – (30 MHz to 300 MHz)
D – (300 MHz to 1 GHz)
E – (1 GHz to 18 GHz)
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.
c. The 75001 point limit is put in place, to keep the mode from trying to build traces that are any bigger than neces-
sary. Basically, enough to cover CISPR Band E (1 GHz to 18 GHz) with its 1 MHz bandwidth, plus a little extra mar-
gin. This same point limit (75001) is applied to the other resolution bandwidths (Res BW), and also to the other
CISPR Band Scan Maximum Span Values (displayed in the third column). There is no direct control permit-
ted over the number of points used in the EMI scans. But, indirectly the SPAN and resolution bandwidth (Res BW)
values, determine the number of points.
Exception: When using Fast SA Scan measurement (displayed in the fourth column), then you can control the
number of points, similar to SA mode, where the point limit then becomes 20001.
338
Chapter 9
174.
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.,
EMI 6 dB Resolution
,
Bandwidthd e
200 Hz
9 kHz
120 kHz
120 kHz
1 MHz (impulse BW)
refer to "Preamplifier Control (Opt 235)" on
Res BW (6 dB) 120
CISPR Band Scan
Maximum Span
b, ,c
Value a
3.735 MHz
168.1 MHz
2.243 GHz
2.243 GHz
17.6 GHz
Keysight N9927-90020 User's Guide
kHz).
CISPR Zoom Scan
Minimum Span
d,e
Value
19.6 kHz
882 kHz
3.96 MHz
3.96 MHz
1.879 MHz