34 Chapter 2
E4438C Vector Signal Generator Overview
Front Panel Display
2. Annunciators
The display annunciators show the status of some of the signal generator functions, and indicate error
conditions. An annunciator position may be used by more than one function. This does not create a problem,
because only one function that shares an annunciator position can be active at a given time.
ΦM This annunciator appears when phase modulation is turned on. If frequency modulation
is turned on, the FM annunciator will replace ΦM.
ALC OFF This annunciator appears when the ALC circuit is disabled. Two other annunciators
appear in the same position: UNLEVEL when the ALC is enabled and is unable to
maintain the output level, and BBG DAC when the waveform data exceeds the DAC
range.
AM This annunciator appears when amplitude modulation is turned on.
ARMED This annunciator appears when a sweep has been initiated and the signal generator is
waiting for the sweep trigger event.
ATTEN HOLD This annunciator appears when the attenuator hold function is turned on. When this
function is on, the attenuator is held at its current setting.
BERT This annunciator appears when the Option UN7 bit error rate test (BERT) functions are
turned on.
ENVLP This annunciator appears if the burst envelope modulation is turned on.
ERR This annunciator appears when an error message is placed in the error queue. This
annunciator will not turn off until you have viewed all of the error messages or cleared
the error queue. You can access error messages by pressing
Utility > Error Info.
EXT1 LO/HI This annunciator is displayed as either EXT1 LO or EXT1 HI. This annunciator appears
when the ac-coupled signal to the EXT 1 INPUT is less than 0.97 V
p
or greater than
1.03 V
p
.
EXT2 LO/HI This annunciator is displayed as either EXT2 LO or EXT2 HI. This annunciator appears
when the ac-coupled signal to the EXT 2 INPUT is less than 0.97 V
p
or greater than
1.03 V
p
.
EXT REF This annunciator appears when an external frequency reference is applied.
FM This annunciator appears when frequency modulation is turned on. If phase modulation
is turned on, the ΦM annunciator will replace FM.
L This annunciator appears when the signal generator is in listener mode and is receiving
information or commands over the GPIB, RS-232, or VXI-11/Sockets (LAN) interface.