18 | Keysight | M9391A PXIe Vector Signal Analyzer - Data Sheet
Description
Specifications
Supplemental Information
Gain
Instrument uncertainty53
DUT gain range = -20 to +40 dB. See note54
< 10 MHz
10 MHz to 6 GHz
± 0.21 dB
53. “Instrument Uncertainty” is defined for gain measurements as uncertainty due to relative amplitude uncertainties encountered in the analyzer when making
the measurements required for the gain computation. See Keysight App Note 57-2, literature number 5952-3706E for details on the use of this specification.
Jitter (amplitude variations) will also affect the accuracy of results. The standard deviation of the measured result decreases by a factor of the square root
of the Resolution Bandwidth used and by the square root of the number of averages. This application uses the 4 MHz Resolution Bandwidth as default since
this is the widest bandwidth with uncompromised accuracy. Under difficult conditions (low Y factors), the instrument uncertainty for gain in high band can
dominate the NF uncertainty as well as causing errors in the measurement of gain. These effects can be predicted with the uncertainty calculator.
54. Uncertainty performance of the instrument is nominally the same in this frequency range as in the higher frequency range. However, performance is not
warranted in this range. There is a paucity of available noise sources in this range, and the analyzer has poorer noise figure, leading to higher uncertainties
as computed by the uncertainty calculator.
Description
Specifications
Supplemental Information
Noise figure uncertainty calculator55
Instrument noise figure uncertainty
Instrument gain uncertainty
Instrument noise figure
See the noise figure table earlier in this chapter
See the gain table earlier in this chapter
See graphs of “nominal instrument noise
figure”; noise figure is DANL + 176.24 dB
(nominal)56
Instrument input match
See graphs: nominal VSWR
55. The Noise Figure Uncertainty Calculator requires the parameters shown in order to calculate the total uncertainty of a Noise Figure measurement.
56. Nominally, the noise figure of the spectrum analyzer is given by NF = D — (K — L + N + B) where D is the DANL (displayed average noise level) specification,
K is kTB (-173.98 dBm in a 1 Hz bandwidth at 290 K) L is 2.51 dB (the effect of log averaging used in DANL verifications) N is 0.24 dB (the ratio of the noise
bandwidth of the RBW filter with which DANL is specified to an ideal noise bandwidth) B is ten times the base-10 logarithm of the RBW (in hertz) in which
the DANL is specified. B is 0 dB for the 1 Hz RBW. The actual NF will vary from the nominal due to frequency response errors.
Nominal instrument NF, 0.01 to 6 GHz, range = -28 dBm
17
16
15
14
13
12
11
10
9
8
7
0
1
2
3
4
5
6
GHz
KEYSIGHT [ Keysight Technologies ]
