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OPERATI NG INSTR UCTIO N S
F
R
ON T-ΡΛΝ [ L 01' Ι It .A f
ION
Front panel operation remains basically ι h e same as for α
standard instrument, except
t
he stan dar d ιΙ 3
d
βιη in 137
dB m range is changed ίο + 13 dΒ m to -97
d
Bm .
Wh en
f
ro nt-panel operatio n is emp loye d, any re mote
p
rogramming co nnecte d to t h e rear -panel LEVEL PR O-
GRAM plug is automatically
d
isable d .
REMOT E PR OG RAMM ING
ΝΟΤΕ
Set the front- ραηe1 Step Atienuator in the REMOTE
position , t h en, connect ιernu te-p ίogrammsng BCD switches
or TT L signals to -he signal ge nerator rear-ραπαΙ LEVE L
PROGRAM
ρΙιι q "α shown in ΤιιΙ >Ιι 1
Α mating μιυ 9 i".
furnis hed with εαεη ιπtt "υιηυητ ,
For example, to program an ατ te πιι tιιί "+ υ 1 106 .5 dB,
pins 14, 1, 8, 10 . and 12 of
t
h e LEVEL PROGRAM nher
must
b
e grounded , t h en to reduce the attenuation by fi d β
(i .e . 100.5
d
B), ground +s removed from pins 7 and Β.
(Note that 0 dB reference point is + 13 d8m.)
REVERSE POWER PR OT ECTIO N CI RC U IT
1f an external RF voltage of approximately 6 VRMS or
m
ore is acci dentally app lied to the inst rument's
R
F O UT
connector, an internal switch in th e Programmable Αtt επ -
uator in series with
t
he RE output will open .
T
his prevents
d
amage to t he instrument's A τ tenuator or Output Am pli-
fίer, This open switch will be in dicated by α (las h ing ηΥ the
UNLEVELE D lam p on the fro nt panel . Once
t
he switc h
is
t
ri pped, it will latc h in the open position
a
nd re main
open υη tίΙ rese ι . Α combination of α ba d mismatch,
h
igh
output level (0.1
V
1, an d changing frequency can also cause
t
he Pr otection Circ ιιί t to tri p.
After removing the RF signal causing the overload, the
switch can
b
e reset by momentarily tu rni ng the front- pan el
AC
P
OWER switch of f.
ΝΟΤΕ
N
or mal operation of the UNLEVELE D lamp is α stea dy
glow if instrume nt is un levele d . Ι 1
t
h e RE circ u it
b
rea k er
is tripped
w
hile the instrum en t is unleveled, the UN-
LEVELE D lamp will vary in inte nsity instea d of flas hing
on and off .
CIRCUIT DFSCRIPTION
{1e Ιιτ so ill,! ΟμΙιππ 1 Α block ι l ιαηr α m αηλ the αςι f ιrο t ιιί;ιι r
,ιΙιι " υι . ιιιί", is, $φ :Ιίιιιι Γι Ιι > follow the είιcιιίΙ ίιι"ηιιιι.ιt ιιπ
containe d in t his section.
REVERSE PO WER PR OT ECTIO N CI R CU IT
T
h e Reverse Power
P
rotection ci rcu itry is located ' π τι""'
Prngcαmmab le Atte nu atnr and in Anenuato r Drive mo dule
Μ41 Α -1, With
t
he instrument's AC
P
OWER switch, tιιωρο
ο"(, ι tιe Ριηιeε t ίοη Circuit internal relay, in se ries with τη e
RF output, is in its normally open position . This prevents
d
αιηα ge to the Attenuator or Output Amplifier if reverse
p
ower is inadvertently app lied to
t
he RE OUT connector
while instrument is
n
ot in use. As soon as AC ρπωει ιs
applied to the instru ment, the επ m ρα rατοr, IC E , will com
p
are the RE
m
onitor voltage to α fixed reference voltage π`
aμμ rox ίmatety 5 volts, As long as the monitor voltage is;
! :"".". 1f ιυι ίι.^ rί ν <ιΙ 1 Γ"""
"" ,r π:, "
ιη r
πιηιηα rαtιχ
υιιΙΙιιιι will
ο ,
αι
a-
, " πχ
ιηαιιίιγ ι ί ' ,
νr,; Ιτ .
Γι is ιιπs ίΙίνε output turn - n
relay drίver 01, whic h energizes
t
h e Proteclior ι C ιιεπί "
,class,
t
hus completing t he RF output circuit.
Τfιυ ςιιι s ίιίνπ output from ICI also turns no 02, ι h "
ef δ: κt ι vely grounding pin 7 of ti mer IC5 ιν h ίε hι cπιe"αιι" -
ατ His αslahle oscillator, Wit h Pin 7 grounded . me ιίιιιer ~ τ
inoperative and its output at pin 3 is "h ig h" . The "ι, ίgfι "
πυιηιιι from IC5
t
urn s off 03 and thu s preven ts the curreετ
ΙΙιία, to ιhι " Ιιπηι ραηι " 1 ONE Γ V rI ΓΠ Ιαιηη.
If all external RE signal exceeding 6 VRMS is a ρp l ίed :ο
she instrument's RF OUT co nnector , the RF mon ί lur
voltage will go above 5 volts. T h is will
p
ro dice a negative
οιιτοιιt from ICI, an d th e feedback pr ovided by ιηε nega
ιίνe latc h diode and resistor will latc h IC E in this state . The
ηι gative output fro m ICl will turn off
r
elay drive, 01 and
cause the
P
rotection Circuit relay to return to its normal!v
υςιρπ ςιπs6t ίπις thereby
r
emoving the external RF τίη,"α '
from the Αtιαπυαtπr circuitry.
Th e ι"ρηαΙίνρ output
from
com μ arator ICl also
t
u rns off
02, thus removing
t
he ground from
p
in 7 of time r IC5,
ωh ιε h allows
t
he timer to oscillate. The output at ρί rι 3
of Ις 5 then
varies
b
etween 0 and +7 volts As the output
sωηιgs down toward 0 volts, 03 tu r ns on and Supplies
curieηt to
t
he fron t panel UNLEVELE D lamp,
t
hen, as
the output rises towards +7 volts. 03 turns off and pr events
current flow
. This on/off cycle of 03 ca uses t h e UN-
LEVELE D la mp to flash .
Th e εο m ρα rατυr can be υηΙσιιΙι ed by mnrnentanly r:
moving AC power to t h e instrument after the εxternx
RF signal is removed-
8/ Ιι .-
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