HP 8340B Manual page 311

J9
-
Internal/JIO
-
External
Use these connectors, and the
INT/EXT
switch, to
select either the internal
10MHz
crystal oscillator
frequency standard, or an external frequency standard as the instrument's master time base.
How to Select the Internal Standard:
1.
Place the switch
in
the INT position.
2.
Connect
a
jumper cable
between the
INT
and
EXT BNC connectors.
How to Select an External Standard:
1.
Check that the source to be used is
10
MHz ±100Hz.
2.
Check that the source
to be used provides
1
to
+10
dBm.
3.
Place the
switch
in the
EXT
position.
4.
Connect the external source to the
EXT BNC connector.
When the switch is in
the EXT position, the internal standard
is turned
off,
and the
amber EXT REF
annunciator comes on
above
the front panel
ENTRY DISPLAY.
J11
—
External Trigger Input
Use this input (2 kf2
nominal
impedance) to trigger the
start of
sweep.
A
trigger signal must be at least
2V (10V maximum),
and
wider
than 0.5 microseconds.
J12
-
Mute Output
This output is
an active low
TTL
signal used to pause external X-Y recorders
or
instruments when the
synthesizer crosses
a
frequency-band switchpoint. For more information
on using an
X-Y recorder,
refer to the
HP 8340B/8341B
Operating Manual.
J13
-
Penlift Output
Penlift disables an
X-Y recorder during
sweep
retrace.
If
you press
[SHIFT] [LINE],
penlift also
disables the recorder during
band
switchpoints.
Penlift
provides
a
current path to ground for
the
recorder's
pen solenoid.
A
zener
diode protects the
penlift circuit
from excessive recorder solenoid voltage, and
a
diode protects
it
from negative voltages
on the input.
J14
—
Negative Blanking
This output provides
a
negative rectangular pulse (approximately —5V
into 2k
Q)
during sweep
retrace
and band switchpoints.
J15
—
Z-Axis Blanking
/
Markers
This output supplies
a
positive rectangular pulse (approximately
+5V
into
2k Q)
during
sweep retrace
and band switchpoints.
When
the RF output
is
at
a marker frequency, this output supplies
a
—5V
pulse.
HP 8340B/41B
Rear
Panel Theory of Operation
G
.43