HP 8340b User Manual

A18
LOW
BAND POWER AMPLIFIER
The
A18
low
band
power
amplifier
is
a
bipolar amplifier
that
provides approximately
40
dB
of
gain
and
20
dBm
of
output
power
from 0.01
to
2.3
GHz.
At 20
dBm,
harmonic
output
is
less than
—25dBc.
The
A18A1
low band
power
amplifier
bias
assembly
provides
the
bias
currents,
the
+20V,
and
the
—10V
required
by
the
A18
amplifier.
The
amplifier and
bias board
are
matched
and
attached at
the
factory; there
are no
adjustments
or
replaceable
parts,
and
the
two
must
be
replaced
together.
When
you
turn
the RF
off,
or
operate
the
synthesizer
in
high
band,
the —10V
bias
is
removed,
shutting
off
the
amplifier.
A63
RF
ATTENUATOR
The
RF
attenuator provides
90 dB
of
attenuation,
in
10
dB
steps.
Combined
with the
range
of the
ALC
loop,
this
gives
the
instrument
a
maximum
setable
power
range
of
+20
to —110
dBm.
The
step
attenuator functions
like
four
fixed
attenuators (one 10,
one
20
and
two
30
dB). Latching
relays
close
contacts
that
either
insert
these
attenuators
in
the
RF
path
or
bypass
them.
The
attenuator
control and
drive
circuitry
is
located on
the
A24
attenuator
driver/SRD
bias
board.
Insertion
loss,
with
0
dB
of
attenuation
selected,
is
less than
2.8
dB
at
26.5
GHz.
J5/J20
RF
OUTPUT CONNECTOR
The
J5
(front
panel)/J20
(rear
panel)
RF
output
connector
is
not
the
same
on
both
the
HP
8340B
and
the
8341
B.
The
HP
8340B
has
a
male,
precision
3.5
mm
connector;
the
HP
8341
B
has
a
female
type-n
connector.
Either
type
has
an
internal
1000
pF
(non-replaceable)
DC-blocking
capacitor.
The
blocking
capacitor
can
handle
up
to
50
Vdc.
ATI
PERIPHERAL MODE ISOLATOR
The
AT1
isolator
provides
20 dB
of
isolation,
and
has
less than
1
dB
of insertion
loss.
AT1
improves
the
match
between
the
high
band
power
amplifier
and
the
switched
YTM.
AT3
ISOLATOR
The
AT3
isolator
improves
the
match
between
the
A15
low
band
low
pass
filter
and
the
A17
low
band
mixer
with 20 dB
of
isolation.
Coupled
RF
from
the
high
band modulator
splitter
is
isolated
from
the
low
pass
filter,
reducing
any
mismatch
signal
propagated
as
video feedthrough.
H-6
RF
Section
Theory
of
Operation
HP 8340B/41B

HP 8340b Specifications

General

Brand	HP
Model	8340b
Category	Inverter
Language	English