HP 8642A Operation And Calibration Manual

Operation
Model 8642A/B
Relative Amplitude (cont'd)
3-80
Display
FREa
AMPTO RE!.,.
The AMPTD REL annunciators indicate the amplitude display is relative to a
reference amplitude. The amplitude is now displayed as 0.0 ciB relative to 20 dBf.
(Note that the amplitude reference would be displayed as -100 dBm because the
reference can only be displayed in absolute units.)
REF SET Example 4
Configure the front panel to display all output amplitude values as an offset from a
12 dBuV amplitude reference. Actual amplitude references in units of dBuV or dB
relative cannot be directly set; however, REi. ZERO ( ( SHIFT I (AMPTD I ) can be
used.
First select ( INSTR .PRESET I to put the instrument in a known state, then:
ENTRY
DATA ENTRY
LOCAL
(keys)
(AMPTO J
OJOJW
[AMPTO I
..
(program
codes)
DispJay
I lit lit lit lit lit lit 171 171 m 7
, ILJ ILJ.ILJ IW IW IW IW IW /1' L
FAEO
AP 12 DU APRZ
8
ENTRY
REt. ZEAO
[AWPTD I
.."..
lit lit TI ]
1U.1t.J .JJ
AMPfO REl
The AMPTD REL annunciators indicate the amplitude display is relative to a
reference amplitude. The displayed amplitude is 0.0 dB; the actual amplitude output
can be displayed (in dBm) by selecting REF SET ( ( SHIFT I I FREQ I ) The dBm key
will function as a dB key when the amplitude setting is relative. (Note that the
amplitude reference would be displayed as -95 dBm because the reference can only be
displayed in absolute units.)
How
to Reference to the Signal Generator's Last-Selected Reference
Turn OIl the amplitude relative mode by setting the amplitude reference to the
last -selected va lue:
( AMPTD I REF SET ([ SHIFT) ( FREQ I) (OFF ON I.
How to Display the Current Reference
[ AMP T D) REF SET ( ("S"'RTI1"IF ..... T.-.l [FREn )
Even though the amplitude reference can be set in dB relative units using the Relative
Zero function, the amplitude reference can only be displayed in absolute units {In this
case, the amplitude setting is automatically converted to absolute units before it is set
as the amplitude reference.}
Clear the reference display by either pressing the [?BWD key twice, or by setting
anot her funet iun

HP 8642A Specifications

General

Brand	HP
Model	8642A
Category	Inverter
Language	English