Wavetek 3001 Instruction Manual page 141

insette d as needed
b
y c losing the
appropriate remote p
rog r am m ing
switc hes . If remote
C W / ΑΜ mode
se
l
ection in to be use
d
, the 1 ιια [ rυιηυιι t
front-panel
M
ODE switch
m
u st be placed
1 η
t
he AM posit i on . C l osing the remote
ςΗ/ ΑΜ switc h sel ects CW
mode,
wh i le
ope ni ng
the switch
se lects
AM
mode .
The instr ument MODULATION FREQ switch
may be p l aced in any position as
required .
Reverse
P
ower P rotect ion
internal swi tc h
1π series wit h the ΑΣ
o utp u t will o p e n . This p reve n ts
d
amage
[ο
t
he in strume n t's
Atte n u ato τ
or
O
utput Amplifier . This open switch
will be indicated on
t
he front pa nel by
th e flashing
o
f
t
he UNLEVELED
l
igh t .
Once t he s witc h Is tri p p ed,
it will
l
atc h
in
t
he open position and
remain
ope n un t il reset . Also, α co mbination
of α
h
igh m ismatc h , high output leve l
(over .1 V) a nd cha ng in g frequency can
ca use t he c ir cu it breaker to trip .
A
f ter removi ng t he RF sig nal cau si ng
the ove rloa d , t h e sw itc h can be reset
by, m o me ntar ily tu r nin g t he front-pane l
AC
P
OWER switc h to t he OFF pos ition .
ΝΟΤΕ
Νοπηα 1 o p e r atio n of t h e UNLEV ELE D
lig h t is α stea dy glow if t h e
i n st r ument is
u
nlevele d .
I
f th e
c i rc u i t brea ker is tri pp e d
wh ile
th e i n st r ume n t is un levele d , t he
UNLE V ELE D lig h t will vary i n
i nten sity
instea d of flas h i ng on
and off .
8/1Β -2
Outp u t
P
rotectio n
Wit h
t
h e i n st r u m e n t's AC POWER switc h
III Ιιιι OFF,
Ιιοιι Lt ion,
the
P
rotection
Ci rcuit in te r na l relay,
i
n series wit h
t
h e RF ou tp u t, 1 α in its normally o pen
posit ion .
This
p r eve nts da mage to the
atte nuators or
O
u tpu t A mpl ifier 1 Ρ
r
eve r se RF power
i
s
in adve r tent ly
ap p l ie d
to t h e
RF OU T connector
w
h ile
in strument
i
s not . in u se . As soon as
A
C power
i
s a p p l ie d to t h e instrument,
Ι C2 Π 1 w il l
co mpare
t h e
ΑΣ
m
o n itor
vo l tage at J201 to α fixe d
r
e f e r ence
vo l tage o f appr oximatel y 5
v
o l ts . As
l
ong as t he R F mo nitor vol tage
i
s
l
ess
t ha n
t
h e
5 vo l t
reference, t
h e o u tpu t
o f IC201
will
be ap proximate ly +17
vo l ts . Th is positi ve out put from IC201
turn s on
t
h e
r e lay driver, Q201, w h ic h
e n e rg iz es the
P
rotectio n Circuit re lay,
t hu s comp l eti n g t he RF o u tput circuit .
Th e pos i tive o u tput fr om
I C201 also
t
u r n s
on
Q202 ;
t h us
eff ective l y
grounding pin 7 o f
ti me r I C202 wh ic h
o
p erates as an astable oscillator .
With p i
n
7 gro,inded,
the timer in
inoperative . and
i
ts outp u t,
pin 3, is
high . Th e high outp u t from
I
C202 t u r n s
off Q213 a n d
t h us
pr events any current
flow to th e
f
r ont-pa n e l
U
N LE V ELED lamp .
If an
e
x terna l ΑΣ sign a l exceed ing 6
VRM S Is app l ie d to t h e instru ment's
ΑΣ
OU T conn ecto r , t he RF mo n itor vol tage
at 3201 w ill go abov e 5 vo l ts . This
will produce α
n
egative o ut p ut from
I
C201, a n d the feedbac k provided by
C R 202 and
R
211 will
l
atc h I C201 in
t
h is
state . T he
n
egat iv e o u t p u t from IC201
will
t
u rn o ff re lay driver Q201 a nd
cause
t
he Protection Circuit relay to
return to
its
normally
ope n
p
ositio n , thereby remov i ng the external
RF s igna l from
the Attenuator
circ u itry .
Th e
n
egativ e
output fro m I C201 a l so
turns
o
ff
Q202, t hus
removing the
gro un d on pin 7 o f
t imer
I
C202, w hic h
allows t
h e
timer to o p erate
as an
α sta b l e osci llator .
Th e o u tput on
p
i n
3 of iC202 th en varies betwee n 0 a n d +7
if an
exte rna l RF vo l tage o f
approximately
6 VRMS or more is
accid en ta ll y app lied to the
i nst rume n t's RF OUT connecto r , an
C I RCU I T D ESC R I P T I O N
The
O p t ion
1 Β overall
Schematic
co ntained
1η t h is sectio n
s
houl d be
used to foll ow t he c i rcuit description
given be l ow .