HP 8591C, User Manual, Page: 112 / 373

I
System Measurements
Making System Measurements
1 9 9 3
R E F 3 7 . 5 10
A I R
H R C T
U S R C H
C N T R
U S R C H
SPAN
C E N T E R 5 7 . 8 8 8
R E S 3 8
S P A N M H z
3 8
RT
Figure 3-1. Channel Tuning Menu
4.
spectrum
analyzers with a 50 input:
Use an external 50 to
75 matching block to compensate for the impedance mismatch
between a 75 impedance system and the spectrum analyzer’s 50 input
impedance. If you use an HP
external pad, the external pad
causes approximately 5.8 of amplitude loss. The external pad function
(EXT PAD YES NO can be used to compensate for this amplitude loss.
l
Connect the matching pad to the spectrum analyzer input.
l
Press Analyzer Input EXT PAD YES NO to underline YES.
l
Press Prev Menu to return to the Setup menu.
If you are using a spectrum analyzer with 50 input impedance but are
not using an external matching
block, the analyzer will compensate
for most of the impedance mismatch, but amplitude measurements can
have up to
additional error caused by the uncompensated
mismatch over the frequency range.
C A U T I O N
dc voltages in excess of 25 V and ac power-line voltages in excess of
100 Vpeak can permanently damage the analyzer input.
3-5