Agilent Technologies E4440A, Service Manual

Page: 169 / 436

Chapter 8 169
Hardware Options
Verifying Option 110
Verifying Option 110
100 kHz to 26.5 GHz Preamplifier (E4440A/43A/45A)
100 kHz to 50 GHz Preamplifier (E4446A/47A/48A)
Option 110 provides approximately 30 dB of preamplification on the
PSA series spectrum analyzers. The range of operation is from 10 MHz
to the upper frequency of the spectrum analyzer. Option 1DS, the
100 kHz to 3 GHz preamplifier, cannot reside in the instrument when
Option 110 is present. Although Option 110 has the same lower
frequency range as Option 123, Option 110 is more expensive and has
slightly different specifications. Therefore, Option 110 will not replace
Option 1DS in all cases.
There are two Option 110 preamplifiers. The 26.6 GHz microwave
version is used on the E4440A, E4443A and E4445A. The 50 GHz
millimeter version is used on the E4446A, E44447A and E4448A. Both
amplifiers require the A38 Option Driver assembly for control of the
amplifier, including flatness compensation files and control of the
mechanical switches that switch the amplifier into and out of the signal
path. The mechanical switches are stand alone components and not
part of the preamplifier or the option driver board.
Verification of Option 110
The input level at the preamp should not exceed -30 dBm in order to
avoid distortion or overload at the preamplifier and first mixer. Assure
the instrument is in Spectrum Analysis mode. To turn on the
preamplifier press the
Amplitude
key and select
Int Preamp On
. Turning
the preamp on or off should produces an audible “click” that verifies the
switch has been energized.
A quick check of the preamplifier consists of viewing a signal on screen
and determining if the signal level is correct. Since the preamplifier
covers a wide frequency range and the flatness of the amplifier is
corrected, it is important to verify the amplifier performance at several
frequencies. Above 3.05 GHz, you must perform a Preselector Center
(
Amplitude
,
Presel Center
) to minimize amplitude error due to the “high
band” preselector.
Frequency Measured Amplitude
Preamp ON Measured Amplitude
Preamp OFF
200 kHz
5 GHz
10 GHz
15 GHz