Hardkey and Softkey Reference ESG Family Signal Generators
AM
4-4 User’s Guide
The wideband AM selection (AM Path WB) eliminates the bandwidth
limitations of the ALC loop thereby increasing the bandwidth beyond
that of the standard amplitude modulation. Typical rates for wideband
AM are listed in the technical specifications document. When you select
AM Path WB in the AM menu, you must apply your modulating signal to
the I input. The sensitivity is 0.5 V = 100% AM depth. With
AM Path WB
selected, the modulated RF signal will be available at the RF OUTPUT
connector when you turn on both
Mod On/Off and RF On/Off.
Default Value: AM Path 1
Softkey Location:
AM > AM Path 1 2 WB
AM Rate
Use this softkey to change the internal modulation frequency for the
AM Path 1 and AM Path 2 configurations. To change the value, press the
softkey once. The current value for AM rate is displayed in the active
entry area. To enter a new value, rotate the front panel knob until the
desired value is displayed, use the up and down arrow keys, or enter the
value using the numeric keypad and press the
Hz or kHz terminator
softkey. The range of values allowed is 0.1 Hz to 10 kHz. (0.1 Hz to
50 kHz is the range allowed if sinewave is selected as the internal
waveform.) The minimum increment allowed is 0.1 Hz. Notice that the
new value of AM rate applies only to whichever AM configuration
(
AM Path 1 or AM Path 2) you have currently selected.
Default Value: 400 Hz
Softkey Location:
AM > AM Rate
AM Source
Pressing this softkey reveals a menu of choices for amplitude
modulation sources. You can choose internally-generated amplitude
modulation or select an externally-applied signal from either the EXT
1 INPUT or EXT 2 INPUT connectors. The internal modulation is
always AC-coupled. For the externally-applied signals, you can choose
between AC- and DC-coupled modulation. A 1.0 Vpk input is required
for calibrated AM depth settings. The
EXT 1 LO/HI and EXT 2 LO/HI
display annunciators will turn on if the peak input voltage differs from
1.0 Vpk by more than 3%. (The LO/HI annunciators only function for
AC-coupled external inputs.)
The internal and external 1 and 2 sources have multiple uses. You can
use them for amplitude, frequency, and phase modulation. For burst
modulation, you can only use the external 1 source and you must use
the external 2 source for pulse modulation. However, any given source
can only be routed to one enabled modulation at a time. If, for example,
you were using the external 1 source in a frequency modulation
configuration for
FM Path 1, and then you configured AM Path 2 to also use
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