HP 8340b User Manual

The remaining bands (7.0
GHz
to
the
maximum
output frequency)
are
generated
by
multiplying
the
YO
frequency
in
the
SYTM.
A
step
recovery
diode
(SRD)
in
the
SYTM,
when
biased
properly,
generates
harmonics
of
the
input
signal.
A
YIG-tuned
filter
tracks
the desired
harmonic,
allowing
it
to
pass
through to
the
high
band
coupler
and
step attenuator
to
the
RF
output.
The
SYTM
driver provides
the
necessary
circuitry for
the
YIG-tuned
filter
in
the
SYTM
to
properly
track
the
YO.
Leveling
in
these
bands
is
the
same
as
in
band
1.
Pulse
modulation
is
produced
by
the
pulse modulator driver
and
two
fast
response
time
pulse
modu¬
lators.
The
low
band
pulse
modulator,
located
just
before
the
low
band
mixer,
is
used
when
the
instrument
operates
below
2.3
GHz.
Operation
above 2.3
GHz
uses
the
high
band
pulse
modulator
inside
the
mod/splitter.
ALC
modulation
(fixed
power, AM,
etc.)
is
produced
by the
ALC
modulator
driver
and
the
ALC
modu¬
lators.
The
low
band
modulator
is
located
in
the
3.7
GHz
oscillator; the
high
band
modulator
is
located
in
the
mod/splitter.
POWER SUPPLIES
The
power
supply produces
eight regulated voltage
levels,
four
positive
supplies
and four
negative
supplies:
•
+22, +20,
+12,
+5.2,
-5.2,
-10,
-15,
and
-40V
The
+22
volt
supply
powers
the
10
MHz
reference
oscillator
heater coil.
This
is
the
only supply
that
actually
produces
an output
when
the
instrument
is
switched to STANDBY.
All
supplies
except
for
the
+
22
volt
supply
are
referenced
either
directly
or
indirectly to
the
+20
volt
supply.
In
STANDBY
mode,
the
+20
volt supply
shuts
down.
This
in
turn
shuts down
the
regulators
for
all
other supplies
(except
the
+22
volt
supply).
NOTE: Although
these
supplies
are
shut
down,
line
power
is still
on,
the
line
module,
transformer,
motherboard, rectifiers,
and
filter
caps
still
have
full
voltage
potentials
on
them.
Therefore,
hazardous
voltages
exist
in
these sections
of the
instrument
even
when
the
front
panel
power
switch
is
set
to
standby.
The
+20,
—15,
-10,
and
—40V
supplies
deliver
current
to
the
low
noise
analog
circuits
and
the
microcircuits.
The
+12,
+5.2,
—5.2,
and
—15V
supplies
deliver
power
to the
digital
and
noncritical
analog
circuits.
Over-temperature protection, current
limit,
and
over-voltage
protection
are
built
into
each
supply.
The
output
voltage
of
each
supply
(excluding
the
+22V
supply)
is
monitored.
If
any
of
these
supplies
drop out
of
regulation,
the
instrument
microprocessor
is
flagged.
HP 8340B/41B
Assembly-Level
Service Overall
Instrument
Theory
A-7/A-8

HP 8340b Specifications

General

Brand	HP
Model	8340b
Category	Inverter
Language	English