HP 8340b User Manual

INCORRECT
SWEEP
If
the
instrument
sweeps,
as
defined
above,
but
the
YO
does
not
sweep
or
the
frequency
limits
are
incorrect,
check
the
two
sweep
ramps
from
the
ASS
sweep
generator assembly,
20-30
SWP
(TP8)
and
VSWP
(TP10).
The sensitivities of
these
lines
are
discussed
below.
YO
sweeps
widths
>5
MHz
are
derived
from VSWP.
Note that the
instrument
sweep
width,
delta
F,
is
related to
the
YO
sweep
width
by
the
harmonic
number
of the band
being
used.
For
example,
if
the
instrument
is
sweeping
from
8
to
10
GHz,
the
instrument
sweep
width
is
2
GHz.
However,
this
is
the
second
harmonic
of
the
YO
—
the
YO
is
actually
sweeping
from
4
to
5
GHz;
a
sweep
width
of
1
GHz.
The
sensitivity of
VSWP
is
+2
volts/GHz
of
YO
sweep
width.
In
the
example
above,
VSWP
should be
a
ramp
starting
at
zero
and
going
to
+2
volts.
If
VSWP
is
correct,
look at
PRETUNE
(TP3)
on
the
A54
pretune/delay
compensation
assembly.
It
has
a
sensitivity
of
—2.5
volts/GHz
of
YO
frequency.
In
the
foregoing
example where
the
YO
swept
from
4
to
5
GHz,
PRETUNE
should
go
from
-10
to
-12.5
volts.
If
PRETUNE
is
correct,
look
at
SENSE
(TP4)
on
the
A55 YO
driver
assembly.
This
point has
a
sen¬
sitivity
of
about
—2.34
volts/GHz
of
YO
frequency.
If
this
is
correct,
the
problem
is
most
likely
in
the
A44
YIG
oscillator
assembly.
YO
sweep
widths
^5
MHz
are
derived
from
20-30
SWP.
The
sensitivity
of
20-30
SWP
is related to
YO
sweep
width
but
changes
depending
upon
the
particular
sweep
width
selected,
as
shown
in
Table
D-2.
Table
D-2.
Sensitivity of
20-30
SWP
Line
Sweep
Width
5
MHz
^
YO
sweep
width
>
500
KHz
500
KHz
2:
YO
sweep
width
>
100
KHz
100
KHz
s
YO
sweep
width
>
10
KHz
10
KHz
^ YO
sweep
width
>
1
KHz
5
KHz
^
YO
sweep
width
>
500
Hz
500
Hz
2:
YO
sweep
width
>
100
Hz
Sensitivity
500
KHz/volt
50
KHz/volt
10
KHz/volt
1
KHz/volt
500
Hz/volt
50
Hz/volt
Verify
that
VSWP is
not
sweeping more
than
0.0
to
15.0 mV
and that 20-30
SWP is
correct.
If
both
of
these
are
correct,
the
problem
is
most
likely in
the
20-30
loop.
HP
8340B/41B
Sweep
Generator
Assembly-Level
Troubleshooting
D-25

HP 8340b Specifications

General

Brand	HP
Model	8340b
Category	Inverter
Language	English