Relative Amplitude; Rel Zero; How To Set The Current Output Amplitude Setting To Be The Amplitude Reference - HP 8642A Operation And Calibration Manual

Model 8642A/B
Description
Procedures
REL ZERO
Operation
RELA TIVE AMPLITUDE
A dEm amplitude setting is actually
8.
setting relative to a I mW reference (even
though the 8642A/B treats dBm as an absolute amplitude unit). With the Relative
Amplitude mode, the output amplitude can be displayed relative to references other
than I mW.
The Relative Zero function sets the current amplitude setting to be the amplitude
reference. The Reference Set function sets the current display to read as an offset
from a specific amplitude reference. Setting a value for Reference Set with the
Off/On key causes the amplitude setting to read as an offset from the Signal
Generator's last selected reference.
Once an amplitude reference is selected, all subsequent amplitude settings are entered
and displayed as relative amplitudes in terms of dB above or below the amplitude
reference. This condition exists until the Relative Amplitude mode is turned off.
The actual output amplitude is equal to the sum of the amplitude reference and the
displayed amplil ude.
Note: Put the instrument in its initialized state by selecting
Ql\fBIR PRESEL).
How to Set the Current Output Amplitude Setting To Be the Amplitude Reference
Setting the current output amplitude as the amplitude reference causes the amplitude
setting display to become 00 dB relative
CAlliiPTIJJ
REL ZERO (C]B!ET] QiJ\iWJ1D)
Example
Set the amplitude to any arbitrary level using the Knob, Step keys, or Data keys. (For
example, you might be setting the level to a reference value that depends on a power
level being measured else\l,'here on a power meter) Then, "zero" the Signal Genera tor's
amplitude display:
ENTRY ENTRY
LOCAL
(keys)
[AMPlO
1
~
REl ZERO
(;,MPTO
1
...
(program
APRZ
codes)
3-77