HP 8753D Option 011 - Page 256

The Frequency
Counter
The
frequency coun
ter is
lo cated
on the
A14
assem
bly
and
can
coun
t
one
of
three
sources:
selected
analog
bus
no
de
A14 fractional-N
VCO
(FRAC
N)
A14
fractional-N V
CO
divided
do
wn
to
100
kHz
(DIV
FRA
C
N)
(frequency range
is 100
kHz
to
16
MHz)
The
coun
ts
are
triggered
b
y
the
phase lo
ck
cycle; one
each
at
pretune,
acquire,
and
trac
k
for
each
bandswitch.
(The service
mo
de,
SOUR
CE
PLL,
m
ust
b
e
ON
for
the
coun
ter
to
b
e
up
dated
at
eac
h
bandswitc
h.)
The
coun
ter
w
orks
in
sw
ept
mo des
or in
CW mo
de. It
can
b
e
used
in
conjunction
with
N
N
N
N
N
N
N
N
N
N
N
NN
NN
NN
NN
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
NN
NN
N
SERVICE
MODES
for
troublesho
oting
phase lo
ck
and source
problems.
T
o
read
the
coun
ter
o
v
er
HP-IB,
use
the
command
OUTPCNTR.
Notes
The
displa
y
and
mark
er
units (U)
corresp ond
to
v
olts.
No
des
17 (1st
IF)
and
24
(2nd
LO)
are
unreliable
ab
o
v
e
1
MHz.
Ab
out
0.750
MHz
is
a
t
ypical
coun
ter
reading
with
no
A
C
signal presen
t.
An
ything
o
ccurring
during
bandswitc
hes
is
not
visible.
Fast-mo
ving w
a
v
eforms
ma
y
b
e
sensitiv
e
to
sw
eep
time.
The
analog
bus
input
imp
edance is
about
50K
ohms.
W
a
v
eforms
up
to
appro
ximately
200
Hz
can
b
erepro
duced.
Analog
In
Menu
Select
this
men
u
to
monitor
v
oltage
and
frequency
no
des,
using
the
analog
bus
and
in
ternal
coun
ter,
as
explained b
elo
w.
T
o
switc
h
on
the
analog
bus
and
access
the
analog
in
men
u,
press:
4
SYSTEM
5
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
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N
N
NN
NN
N
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N
N
N
N
N
N
N
N
SERVICE
MENU
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
NN
NN
N
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N
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N
N
N
N
N
N
N
N
ANALOG
BUS
ON
4
MEAS
5
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
NN
NN
N
N
N
N
N
N
ANALOG
IN
The
N
N
N
N
N
N
N
N
N
N
N
N
NN
NN
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
NN
NN
N
N
N
N
N
N
N
N
N
RESOLUTION [LOW]
key
toggles b
et
w
een
lo
w
and
high
resolution.
Resolution Maxim
um
Signal
Minim
um
Signal
LOW +0.5 V 0 0.5
V
HIGH +10
V
0
10
V
DRAFT
3/21/106 15:14
Service Key Menus and Error Messages 10-17
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