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co u nte r's range,
s
uc h as 600 MHz. Sol the front-panel
controls as follows :
F
R EQ VERN I ER
CA L
MOD ULATIO N MO
D
E
CW
MOD U LATIO N FRE
D
ΕΧΤ
M
OD ULATIO N FWAM
minimum
OUTPUT VERN IER
Full εω
OUTPUT Step Attenuator
+10
d
βm
METER FUNCTIO N
O UTPUT
Adjust the Μ30 .1
F
re que ncy Adjust trimmer (Figure 5-51
for α minimum-frequency indication an t h e co u nter, then
carefully turn the Frequ ency Adjust trimmer cloc k wise
until the counter indicates the frequency selected by
L
ever/
In dicator switches . Disconnect
t
he counter fro m the
R
F
O UT connector. Α fi nal fr eq ue n cy c hec k will be covered in
Section 5.3 .12 .
5.3 .5
PHASE-LOCKED
L
OO P Τ ADJUSTMENT Μ31 Α
No adj ustment of mo
d
ule Μ31 Α is
n
ecessary .
53 .6
PH AS E-LOC KE D
L
OO P 2 A
D
JUSTMENT Μ32 Α
See
F
igure 5-5 fo r location of Μ 32Α test
p
oints and Fig ure
5 ά fo r adjust ment controls . Set
t
he
L
ever/Indicator
switches to 200.000 MHz and α!1 other
f
ro nt-parιel co ntrols
as in Section 5,3.4 . Connect α
d
igital voltmeter to Μ 32Α
pi n 14, and care fully adjust hoth Crystal Reference trinimprs
(Α and Θ) to
p
rodu ce α minim um reading on
t
he volt mete r.
This voltage should be
b
etween +0 .5 and +3 .0
U
DC . Set t h e
Lever/Indicator switc
h
es to 239.000 MHz and note t h at the
DVM readi ng is still within
t
he above li mits.
Set
t
h e
L
ever/Indicator switches to 200.000 MHz an d
connect the scope vertical input (DC, 1 VJd ι vis ιon) to
Μ32 Α pin 15 . Adjust Μ32Α control (Α ) for α 0 V scope
indication. Set
t
he
L
ever/I nd icator s
w
itch es to 239 .000
MHz
a
nd adju st Μ32Α cont r ol (Β ) to again
p
ro du ce α 0 V
scope indication .
5.3 .7
PH AS E-L OC KE D
L
OO P 3 AD JU ST MENT
PLL 3 co nsists of two
m
odules : The M33-2 and the M9W.
The test point ά on
m
odu le Μ33-2 ( Figure 5-5) . while the
adjustment controls
a
re on
m
o du le ΜgW ( Figure 5ά) . Set
the Lever/indicator switches to 250.000 MHz and all
other front-panel controls as in Sectio n 5.3 .4. Connect the
scope vertical inpu t (DC, 1 Vidivision) to M33.2 pin 5.
Adjust ΜgW co ntrol ID) for α 0 V scope
i
ndication.
Set the front-panel controls as follows ;
M
OD UL ATION M OD E
FM x10
M
OD ULATIO N FREQ
1 kH z
5-4
M
OD
U
l ΑΤΙΟΝ FM /ΑΜ
Fu ll up
Set t he scope ν ert ίρΙ in pu t I0 n M33.2 p in 5) for AC 50
ιιιV /
d
ίνίsιυπ. Adj u st
M
9
W
cυυ 1ιιι1 (C) lot ιπίιιιιιιυιιι (ιυιΙΙ )
in dication π1 t h e 1 kH z si ne wave on the scope,
53 .8 P H ASE -LOC KE D
L
OO P 4 AD JU STMEN T
Cal ibrat ιoιι of PLL 4 involves t hree mo
d
u les : Μ 172, Μ9W,
and Μ34, Test points are located on
m
odules M172 and
Μ34 (see Figure 5-5), w h ile adjustme nt controls are located
on mo du les Μ 172
a
nd Μ9W (see Figures SA and 5-6) .
Set the Lever/Indicator switches to 250.000 MHz and all
ot her fiont-ραπeΙ controls as in Section 5.3 .4. Connect α
d
igital voltmeter to Μ 172 pin 1 ; them, adjust Μ 172 250
MHz
A
di fo r α 0.00 V rea
d
ing on
t
h e volt mete r. The
νο 1 ιηιe ιer may o0w, be disconnected
C οππeι_t , frequency επιιπτe, to -h e RF
O
UT co nnector
and εοηιικι.ι t he sεοΛε vertical input (DC, 1 V/division) to
Μ34 pin 8 . Ad just Μ9W co ntrol (Α)
f
or 0 τ 1 V on
t
h e
scope,
T
he co unter shoul
d
in dicate α frequ ency ο1 250
MHz
NOTE
Me to the way the M34 locks on harmonics of 40 MHz. it
is possible to adjust Μ9W control (Α) for 0 V at multiples
of 40 MHz
o
f fset f rom 250 MHz- I f this
h
app ens, it will
b
e
n
ecessary
to
readju st
M
9W co ntrol ( Α ) several
turns to
b
rea k lock and relαk at t he next mu ltiple of 40 MHz
u
ntil
0 "1 V can
b
e obtained with α 250 MHz co un ter reading.
Set the
output
frequency
to
300
MHz
and
a
djust Μ 172
300 MHz A
d
i for 0 τ 3 V on the scope with α co u nter
reading of 300 MHz .
R
epeat this step . using
t
he applica ble
Μ 172 Αdj for frequencies of 350, 400, and 450 MHz
Set
t
he
L
ever/Indicator switches (ο 500.000 MHz,
A
djust
Μ 172 500 MHz Adi for α scope reading near 0 V Increase
the
L
evε>rllndicator switch setting to 520.000 MHz and
ηιιι e
t
he scope in dicatio n; then, adjust Μ 172 500 MHz
ΛοΙ to give scope Indlcatiom at 500.000 and 520.000
MHz
t
hat ate, symmetrical about 0 V .
Set
t
he
L
ever ji nd ι cato r switches to 100.000 MHz an d
α dj ιιττ Μ 172 100 MHz Αλ j fo r 0 τ 3 V on
t
he scop e and α
counter reading of 100 MHz-
R
epeat using t h e appropriate
Μ 172
A
di
f
or frequencies of 50 and 0 MHz. (Set
L
ever!
Indicator switches to 001 .000 MHz for 0 MHz
a
dj ustment .l
Connect
t
he digital voltmete r to Μ34 p in 14 ( Leveler ΤΡΙ .
Ste p through
t
h e fre qu ency range from 1 to 520 MHz in 10
MHz ττ eρτ to fin
d
t
he frequency
h
aving the
h
ighest leveler
voltage, then adjust
M
9
W
cont rol (8) for 0 .0 VDC at this
freq uency setti ng.
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