HP 3326A Operating And Reference Manual page 55

Modulation
lnternal
AM1 %AM
Internal amplitude modulation is enabled in the 2 CHANNEL mode when the channel
A INT AM (INternal Amplitude Modulation) indicator is illuminated. lnternal amplitude
modulation uses the channel B synthesizer as the modulation source for channel A,
thus only the channel A output is active. For internal amplitude modulation, 100 kHz
is the maximum channel B frequency, lnternal amplitude modulation limits the values
entered for the channel A amplitude to 50% (6.02 dB) of the normal range.
When internal modulation is selected, the channel B high voltage option is disabled.
If internal modulation cannot be selected (i.e. the INT AM indicator does not illuminate),
check that the 2 CHANNEL mode is selected, COMBINED operation is disabled, and
the channel B frequency is below 100 kHz.
HP-1%
Example:
"AIAl
"
or
"AIA ON"
Percent
A M
The %AMIPM DEV (percent Amplitude ModulationlPhase Modulation DEViation) key
enables display, entry, or modification of the modulation percentage. The %AMIPM
DEV key is selected by pressing the blue SHIFT key prior to the AMPTD key. The
%AMIPM DEV indicator illuminates when the modulation value is displayed. After selec-
tion of the %AM/PM DEV key, the modulation value is entered or modified with the
numeric keypad and
O/ O
units key, or modified with the MODIFY controls. The modula-
tion value ranges from 0 to 100% with 0.1
O/ O
resolution. With 0 % amplitude modula-
tion, the channel A output level is equal to the amplitude entered for the AMPTD key.
The modulation value is used for both AM and PM. If the displayed modulation value
is in degrees, pressing the % units key converts the displayed value to percent. Simi-
larly: if the displayed value is in degrees, pressing the DEG units key converts the dis-
played value to degrees.
HP-1% Example: