Wavetek 3000 - Dividers; Multipliers; M31 A - kHz Steps; VCO Operation

THEORY OF OPERATION
3 .11 .2
DIVIDERS
The frequencies
below 40 MHz are pro-
duced by a
series of TTL counters . A
"divideby 4"
produces the 10 MHz out
put
for the

phase-
locked

loop in the
optionalhigh
stabilityreference . This
frequency is further
divided as shown
in
Figure 3-16 to provide the 1 MHz, 2
kHz
and 1 kHz outputs .
3 .11 .3
MULTIPLIERS
The 40 MHz CW is fed to
a harmonic gen-
erator which produces the "comb"output
.
From the 40 MHz comb, 120 MHz is selected
and applied to another harmonic
genera-
tor . A sample
of the 120 MHz comb output
is also fed to a filter which
provides
the 1440 MHz output .
3 .12 M31A
- kHz STEPS
The input to this module is the
BCD data
from
the front-panel
"kHz" switches (to
3-16
21WHz
Figure 3-16 .
/MHz
M30 - Crystal Reference
3 .12 .1
VCO
/ A042
40
Milt
COME
3
.12 .2 PHASELOCKED
LOOP
120
MWs

?p0 M .fis~
COMA
/440 MVL
the right of the decimal
point) .

The
output
frequency is (10 MHz - Sk
kHz),
where
Sk
is the
number indicated by the
kHz switches .

If the
FREQUENCY is set
to 333 .333
MHz, for
example, the M31A
output
is 9 .667 MHz . The block
diagram
of
the M31 is shown in
Figure 3-17 .
The output
frequency is
generatedby a
Voltage
ControlledOscillator which
is
tuneablefrom 9 .001
to 10 .000 MHz .
Including
the VCO in a phase-locked
loop
permitsaccurate
programmability . The
VCO
tuning voltage comes
from the Phase/
Frequency
Detector circuit .
A 1 kHz
signal from
the Crystal Reference
is
applied to one
input of the phase detector
(IC9)
.

A sample of
the VCO input is
divided
by the Programmable
Divider, . and
the
result is applied to the
other input
of the phase
detector .

Any
difference in