C3162 -Modulation Board; Dps2A-Power Supply; Delete D - Wavetek 3001 Instruction Manual

3 .3 .4
UNLEVELE
D
L
IG
H
T
Α light emitting diode is mounted on
t
his assembly and
appears no
t
he front panel η1 IN! ιnstrumm ι 1 . Refer to the
Output Amplifier mικk ιΙ e description for an exptaiiation
of the circuit driving this light .
3.4
C3162 -MODULATION BOARD
This assembly provides the modulating signals used in
t
he
AM and FM modes. The front-panel ACCURACY lights
and associated circuitry are also on this assembly (see
F
ig
u
re 3- Θ ) .
3.4 .1
M
ODULATING SIGNALS
The AM or FM modes are achieved by simply routing
essentially the same signal to the appropriate circuitry
b
y means of the front-panel
M
ODULATION MODE switch-
The front-panel
M
ODULATION FRED switch selects
one of four sources of modulating f requency, one external
and
t
hree internal
T
he ι memal signal can be selected
f
rom one of two CW oscillators or α m απυαΙΙγ variable
DC control.
The two internal oscillators are amplified/leveled by the
same circuit for simplicity, but separately energized by
t
he
MODULATION FRED switch . The oscillators are twin Τ
oscillators, one is at 400 Hi, the other is at 1 kHz.
3.4_2 ACCURACY LIGHTS
The CAL
s
witch
on
t
he FREQUENCY VERNIER (or
an
input from Option 5 or 5ΑΙ determines which lamp is [it-
If any of
t
he phase-I ncked Ιοορs
u
nlack. the energize d LED
is made to flash by an IC timer activated 4Υ α DC level from
any of the phase locked loops in the instrument
3.5 OPS2A- POWER SUPPLY
The DP52A provides DC Power for
t
he rest π1 the
instrument Isee Figure 3-101 .
3.5.1 TRANSFORMER &
F
ILTERS
The transformer steos down the line voltage to αρριομηατε
levels for the three circuits . Full wave
r
ectifiers and
f
ilter
capacitors convert this voltage to DC .
3.5 .2
+18 V S
UPPLY
The +ΙΘ V circuit has α temoeralure+compensated precision
voltage reference.
T
his reference is compared to the output
voltage
b
y an
e
rror amplifier which corrects any error in
t
he output voltage .
35 .3 18 V
S
UPPLY
The ~18 V circuit compares the +18 V
a
nd -18 V πυ tρυτs
.ιιι 11 ΙιιΑλτ ιΙιι " difference in their magnitudes (ο τε rπ
3.5 .4 +7,3 V
S
UPPLY
T
he -7 .3 V ει rευ :t uses α three-terminal adjustable voltage
r
egιι lator IC to
p
rovide α pre- ι egulated +7 .3 V αυτρυι . This
νοΙ 1αφ supplies other voltage regulator: throughout the
ι nstr umeη t .
3.8 DELETE D
3.7 Μ gW-SWEEP OSCILLATOR
The Μ9W is the origin of the instrument's RF ου [ρυι
frequency, This frequency is generated by hετer οdγn, ηρ
the signals from two h
igher frequency voltage-controlled
oscillators (see Figure 3-12) .
3.7,1 MIXER
The Ναποω Oscillator applies α signal of 1198 MHz to tηε
mixer . The Wide Oscillator provides
b
etween 1199 and
1718 MHz _ The d ifference (1 520 MHz) is applied to α
wide hand pre-amp and
t
hen sent to the Output Am ςNifier,
3.12
W
IDE OSCILLATOR
T
he wide range of oscillation is achieved by applying an
απαΙπη signal which is dependent upon the setting of the
L everilndicatoι iwitches on the instrument's front panel
to varactnr diodes in
t
he tank circuit, An additional signal is
applied to the VCO from the Phase
d
etector in M34 . This ~s
the
f
ine tuning signal wh ich locks
t
he
W
ide Oscillator on
t
he proper
f
requency .
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