Resolution Bandwidth (Rbw); Power Bandwidth Accuracy - Keysight M9290A Manual

Description

Resolution Bandwidth (RBW)

Range (3.01 dB bandwidth)

Power Bandwidth Accuracy

RBW Range
1 Hz to 750 kHz
820 kHz to 1.2 MHz
1.3 to 2.0 MHz
2.2 to 3 MHz
4 to 8 MHz
Accuracy (3.01 dB bandwidth)
RBW Range
1 Hz to 1.3 MHz
1.5 to 3.0 MHz
4 to 8 MHz
c
Selectivity (60 dB/3 dB)
a.
The noise marker, band power marker, channel power and ACP all compute their results using the power bandwidth of
the RBW used for the measurement. Power bandwidth accuracy is the power uncertainty in the results of these
measurements due only to bandwidth-related errors. (The analyzer knows this power bandwidth for each RBW with
greater accuracy than the RBW width itself, and can therefore achieve lower errors.) The warranted specifications shown
apply to the Gaussian RBW filters used in swept and zero span analysis. There are four different kinds of filters used in
the spectrum analyzer: Swept Gaussian, Swept Flattop, FFT Gaussian and FFT Flattop. While the warranted
performance only applies to the swept Gaussian filters, because only they are kept under statistical process control, the
other filters nominally have the same performance.
b.
Resolution Bandwidth Accuracy can be observed at slower sweep times than auto-coupled conditions. Normal sweep
rates cause the shape of the RBW filter displayed on the analyzer screen to widen by nominally 6. This widening
declines to 0.6 nominal when the Swp Time Rules key is set to Accuracy instead of Normal. The true bandwidth,
which determines the response to impulsive signals and noise-like signals, is not affected by the sweep rate.
c.
The RBW filters are implemented digitally, and the selectivity is designed to be 4.1:1. Verifying the selectivity with
RBWs above 100 kHz becomes increasing problematic due to SNR affecting the 60 dB measurement.
Specifications
1 Hz to 8 MHz
Bandwidths above 3 MHz are 4, 5, 6, and
8 MHz.
Bandwidths 1 Hz to 3 MHz are spaced at
10% spacing using the E24 series (24 per
decade): 1.0, 1.1, 1.2, 1.3, 1.5, 1.6, 1.8, 2.0,
2.2, 2.4, 2.7, 3.0, 3.3, 3.6, 3.9, 4.3, 4.7, 5.1,
5.6, 6.2, 6.8, 7.5, 8.2, 9.1 in each decade.
a
b
Supplemental
Information
1.0% (0.044 dB) (nominal)
2.0% (0.088 dB) (nominal)
0.13 dB (nominal)
0.22 dB (nominal)
0.32 dB (nominal)
2 (nominal)
8 (nominal)
16 (nominal)
4.1:1 (nominal)
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