HP 8340b User Manual

A9
LOW
BAND
PULSE MODULATOR
The
A9
pulse
modulator
is
a
shunt
PIN
diode
modulator
that
provides
an
on/off
ratio
greater
than
80
dB
in
low
band.
Modulator control
is
the
LOPMOD
DR
(low
band
pulse
mod
drive)
signal
from
the
A21
pulse
modulator driver
assembly.
A10
DIRECTIONAL
COUPLER
The
A10
directional
coupler
has
a
—16
dB
coupling coefficient.
The
reverse-coupled
port
is
termi¬
nated.
The
coupled
output
is
sent
to the AH
high
band
detector
for
leveling
in
the
higher
bands.
Although
the
low
band
output
passes
through
the
A10
directional
coupler,
it
does not
affect
low
band
leveling.
The
insertion
loss
is
less
than
1.3
dB
at
26.5
GHz.
All
HIGH
BAND
DETECTOR
The
AH
high
band
detector detects
the
RF
amplitude for
leveling
in
high
band,
producing
a
positive
output
voltage proportional
to
the
RF
power.
The
detector
output
is
sent to
the
A25 ALC
detector
assembly
for
processing.
A12
LOW
BAND
SPLITTER/DETECTOR
The
A12
low band splitter/detector
samples
and
detects
the
RF
amplitude
for
low
band
leveling.
It
consists
of
a
resistive
power
splitter,
and
a
schottky diode detector
that
produces
a
positive output
voltage proportional
to the
RF
power.
The
LDET
BW
(low
detector
bandwidth
control) input (from
the
A26
linear
modulator
assembly)
switches
in
additional
filtering
for
leveling
below
400
MHz.
A
thermistor (mounted
inside the splitter/
detector
package)
compensates
for
detector
temperature
variations.
A13
SWITCHED
YIG-TUNED
MULTIPLIER
(SYTM)
The
A13
SYTM
uses
a
PIN
diode
switch to
turn
the band
0
signal
off
when
you
select
band
1-4.
In
band
0,
the
SYTM
provides
a
straight path for
the 0.01 to
2.3
GHz
RF
signal
from
the
A12
low
band splitter/
detector.
Low
band insertion
loss
is
typically
less
than
0.5
dB.
For
high
band,
the
RF
input from
the
AT1
isolator
is
fed
to the
SYTM.
This
signal
is
applied
through
an
impedance
matching circuit
to
an
SRD
(step
recovery
diode)
to
produce
an
output
rich
in
harmonics.
The
SRD BIAS
applied to
the
diode
is
different
for
each
band
to
optimize
the
harmonic required
for
that
band;
Band
1
=
fundamental
Band
2
=
second
harmonic
Band
3
=
third
harmonic
Band
4
=
fourth
harmonic
(HP
8340B)
H-4
RF
Section
Theory
of
Operation
HP
8340B/41B

HP 8340b Specifications

General

Brand	HP
Model	8340b
Category	Inverter
Language	English