Operation
Modulation, Pulse (cont'd)
Model 8642A/B
Example
Pulse modulate
the RF
output using
the
internal modulation oscillator
at a 2 kHz
rate
(starting with pulse modulation
off).
LOCAL
(keys)
4aa^
(program
codes)
I SHIFT
]
ENTRY
PULSE
1
AM
]
MODULATION SOURCE
1
INT
)
ENTRY
f MOD
|
1 FREO
1
DATA
lAJGL)
( SHIFT
1
ENTRY
r^
1
0FF
1
(
AM
J I
ON
J
PLNT
MF 2 KZ
PLON
Display
fU
0 U.F R
2.B
BE HZ
PUL
£ E
INT
-/W0.0JJ/I?
AMPTD
The
RF
output
is
being internally pulse modulated
(as
indicated
by the
word PULSE
and
the
annunciator
INT).
Modulation frequency
is set to 2 kHz. The
duty cycle
is
50%.
The
cursor above
the
pulse modulation display indicates that pulse modulation
can
be
toggled
off and on by
selecting
the [ OFF ON ) key.
(Note that
the AM
annunciator
is
displayed
if the
word "PULSE" can't
be
displayed.)
EXTDC
How
to Set
Pulse Modulation with
an
External Source
Source
/VWWVWV\WM\\
CAUTION
|
Do
not
apply more than
15 Vpk to the
AM/PULSE INPUT
or
damage
to the
Signal Generator's circuitry could result.
Connect
the
external modulation source
to the
AM/PULSE INPUT connector (input
impedance
of 600
ohms)
and
select PULSE
(
1
SHIFT
i
fMAl
)
1
EXT DC ].
Adjust
the
external modulation signal
to a
level above
1.5
volts. Above
1.5
volts
the
output
is on
and below
1.5
volts
the
output
is off.
Pulse repetition rate
and
duty cycle
are
determined
by the
external pulse generating
source. (Note that
the HI, LO
annunciators
are not
used
for
pulse modulation.)
NOTE
External modulation freqency
is not
monitored
by the
Signal
Generator.
The
Signal Generator's modulation frequency display
refers
to the
internal modulation oscillator only.
3-128
To Next Page
