HP 3326A Operating And Reference Manual page 58

Modulation
External A M
Either channel is amplitude modulated by an external source through the rear panel
A-AMPTD MOD IN (channel AAMPliTuDe MODulation INput) or B-AMPTD MOD IN (chan-
nel B AMPliTuDe MODulation INput) connector when the respective channel EXT AM
(EXTernal Amplitude Modulation) indicator is illuminated. The voltage range for the
A-AMPTD MOD IN or B-AMPTD MOD IN connector is
+
1.0 volt. A 2 volt peak-to-peak
input results in 100% modulation. A 0 volt input results in an output equal to the ampli-
tude entered for the AMPTD key. For channel A, a
-
1 volt input results in a minimum
level. For channel B, a
+
1 volt input results in a minimum level. The maximum ampli-
tude modulation frequency into the HP 3326A is 100 kHz. Amplitude modulation limits
the values entered for the channel A amplitude to 50% (6.02 dB) of the normal range.
HP-16 Example:
' A E A I
"
or
"AEA ON"
"BEAI
"
0
r
"BEA ON"
External P M and Sync PM
External phase modulation is enabled when the EXT PM (EXTernal Phase Modulation)
or (AB) SYNC PM (channel A and B SYNChronous Phase Modulation) indicator is illumi-
nated. Channel A is phase modulated by an external source through the rear panel
A-PHASE MOD INlSYNC PM IN (channel A PHASE MODulation INput/SYNChronous
Phase Modulation INput) connector when the channel A EXT PM or (AB) SYNC PM indi-
cator is illuminated. For synchronous phase modulation, channel B phase is held cons-
tant relative to the channel A phase. Channel B is phase modulated by an external source
through the rear panel B-PHASE MOD IN (channel B PHASE MODulation INput) con-
nector when the channel B EXT PM indicator is illuminated. The voltage range for the
A-PHASE MOD INISYNC PM IN or B-PHASE MOD IN connector is
+
1 .O volt which cor-
responds to
+
360" phase modulation. A 0 volt input results in an output with 0' modu-
lation. The maximum frequency into the HP 3326A for phase modulation is 5 kHz. Phase
modulation selection is dependent on the mode selected (see Figure 1-23).
2 Channel Mode
Channel A is phase modulated by an external source through the rear panel A-PHASE
MOD INISYNC PM IN connector when the channel A EXT PM indicator is illuminated.
Channel B is phase modulated by an external source through the rear panel B-PHASE
MOD IN connector when the channel B EXT PM indicator is illuminated.