Ref Set; How To Set A Reference To A Specific Amplitude (In Units Of De Relative; For Example, Def Or Dev) - HP 8642A Operation And Calibration Manual

Model 8642A/B
Operation
Relative Amplitude (cont'd)
REF
SET
REF SET Example 2
Configure the display to read each subsequent amplitude in dBf (that is, dB relative to
1 femtowa tt: 0 dBf
=
-120 dBm).
First select ( INSTR PRESET I to put the instrument in a known state, then:
ENTRY ENTRY DATA
LOCAL
(keys)
[AMPTO
I
(SH1flJ
REF SET
EJ
c=J CD CIJ
[QJ [];J
dim
..
(program
APRS -120 OM
codes)
Display
I
0 0.0 0
[1
PI PI 0
m z
FREO
AMPTD AEl
The AMPTD REL annunciators indicate the displayed amplitude is relative to a
reference amplitude. The displayed amplitude is - 2 0.0 dB (dBf, in this case). The
actual output amplitude is the displayed amplitude plus the amplitude reference;
therefore, -20 dB
+
(-120 dBm)
=
-140 dBm.
How to Set a Reference to a Specific Amplitude
(In units of dB relative; for example, dBf or dBV)
If the output amplitude has already been set to be displayed in relative units (for
example, dBf or dBV), use the following procedure to set a specific amplitude
reference:
I AMPTD I followed by the value of the desired reference amplitude (in relative dB
units) and REL ZERO (( SHIFT I ! AMPTPl )
REF SET Example 3
Configure the front panel to display all amplitude output values as an offset from a
20 dBf amplitude reference.
First set the display to read amplitude in dBf using the Relative Zero function as
described in "REF SET Example 2" above, then proceed with the following example:
ENTRY DATA ENTRY ENTRY
LOCAL
(keys)
IAMpm}
CIJ
OJ
de
[AMPTO )
8
REL ZERO
~
[AMPTD
I
dBm
..
(program
AP 20 DB APRZ
codes)
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