Agilent Technologies N9010A - Manual (Page 141)

Chapter 13 141
Option P03, P07, P13, P26, P32 and P44 - Preamplifier
Other Preamp Specifications
Other Preamp Specifications
Description Specifications Supplemental
Information
Preamp (Options P03, P07, P13, P26, P32
and P44)
a
a. The preamp follows the input attenuator, AC/DC coupling switch, and precedes the input mixer. In
low-band, it follows the 3.6 GHz low-pass filter. In high-band, it precedes the preselector.
Gain Maximum
b
b. Preamp Gain directly affects distortion and noise performance, but it also affects the range of levels that
are free of final IF overload. The user interface has a designed relationship between input attenuation
and reference level to prevent on-screen signal levels from causing final IF overloads. That design is
based on the maximum preamp gains shown. Actual preamp gains are modestly lower, by up to nomi-
nally 5 dB for frequencies from 100 kHz to 3.6 GHz, and by up to nominally 10 dB for frequencies
from 3.6 to 44 GHz.
100 kHz to 3.6 GHz +20 dB (nominal)
3.6 to 26.5 GHz +35 dB (nominal)
26.5 to 44 GHz +40 dB (nominal)
Noise figure
100 kHz to 3.6 GHz 8 to 12 dB(proportional to
frequency) (nominal)
3.6 to 8.4 GHz 9 dB (nominal)
8.4 to 13.6 GHz 10 dB (nominal)
13.6 to 44 GHz Noise Figure is
DANL + 176.24 dB
(nominal)
c
Note on DC coupling
d
c. 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 (Refer to page 143 for DANL with
Preamp),
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.
d. The effect of AC coupling is negligible for frequencies above 40 MHz. Below 40 MHz, DC coupling is
recommended for the best measurements. The instrument NF nominally degrades by 0.2 dB at 30 MHz
and 1 dB at 10 MHz with AC coupling.