Operation - Wavetek 188 Instruction Manual

VCG
and main
dial within
a
frequency
range.
Linear operation
is
selected
when
the button
is
extended. Logarithmic
operation
is
selected
when
the button
Is
depressed.
8,
SGenerator
MODE
Controls
-
Selects
one
of
the following three
modes
CONT
—
8 released
Continuous
output at
501)
OUT
15
and 16
and
SYNC OUT
(TTL)
17 connectors.
TRIG
—
8 and
9
pressed
DC
level
output
until
generator triggered
by
the
MAN
TRIG
11
or with a
signal at the
TRIG
IN
connector
18
When
triggered, the
generator output
is
one
cycle
of
waveform
followed by
a
dc
level
GATE
—
8 pressed and
9 released
As
for
TRIG
except
the output is
continuous
for
the
duration
of the
manual
or
external
trigger signal
The
last
cycle
started
is
always completed
10
TIME Knob
-
Sots the swoop time
by control-
ling
tho
period
of the
sweep ramo
generator
1
1
Manual
Trigger Button
—
Triggers
or gates
the
output signals
whon
generator mode
is
TRIG
or
GATE
(8
pressed)
In trigger
mode, one
waveform
cycle
is
output
when
the
button
is
pushed
In
gate
mode, wavotorm
cycles aro con-
tinuously output as
long
as
the button
is
held
m
12
FUNCTION
Selector
—
Selects
one
of throe
wavoforms
or
when
all
three
buttons are released,
a
dc
lovol
13
DC
OFFSET
Control
-
Offsets the 500
OUT
waveforms
or gives dc levels
from
-
10V
to
+
lOV(-5Vto
+ 5V
Into
500)
at
15
and from
-IV
to
+
IV
(-0.5V
to
+ 0 5V
into
500)
at
16
An
OFF
position
ensures no
offset.
14
AMPLITUDE
Control
-
Ccw
rotation
reduces
waveform
amplitudes
at
15 and 16 by
30
dB DC
and
offset
voltages are not affected
by
this control.
15
500
OUT
HI
Connector
—
The main output of
tho generator
at
the function selected
Maximum
20 Vp-p
(lOVpp
into
500) with
30
dB
continuous
amplitude
control.
500 source
impedance
16
500
OUT LO
Connector
—
Same
as 15
ex-
cept
20
dB
(1/10)
lower
in
amplitude.
17
TTL
OUT
Connector
—
A
TTL
square
for
each
cycle
of
the generator
To be used
for
syn-
chronization or
as
a TTL
signal
capable
of driv-
ing
20 TTL loads
18
TRIG
IN
Connector
—
Accepts a
TTL
signal to
trigger or
gate the generator. Triggers
on
the
ris-
ing (low to high) transition
and
gates
during the
positive (high) portion
of
the triggering signal.
19
SWP
OUT
Connector
—
Supplies a
ramp
waveform
with
an approximate 4V peak
into
an
open
circuit.
For
use as
a
horizontal drive signal
Source impedance
is
6000
20
GCV OUT
Connector
-
Provides a 0
to
4V
open
circuit
output proportional to the frequency
Of the
main
generator. For use as a
horizontal
drive signal
Source
impedance
is
6000
21
VCG
IN
Connector
—
Accepts ac
or
dcvoitagos
to
proportionately control
frequency
within the
range dotormined
by the
FREQUENCY
MULTIPLIER
4
.
Positive
voltage increases the
frequency
set
by
the
d-ai 1
;
negative voltage
decreases
the
frequency The
VCG
IN
will
not
drive the
generator frequency
beyond
the nor-
mal
dial limits
Of
a rango
Input
impedance
is
2 kO
3.2
OPERATION
Perform
the
initial
checkout
in
Section
2
tor
the
tool
of
the instrument.
Any
questions
concerning
Individual
controls and
connectors
may
be
answered
In
paragraph 31
3.2.1
Signal
Termination
Proper signal termination, or loading, of the generator
connectors
>s
necessary
for
its
specified operation.
For example,
the proper termination
of either
of
the
500
OUT
connectors is
shown
in
figure 3-2 Placing
the
500 terminator, or
50Q
resistance,
in
parallel
with
a higher
impedance, matches
the receiving
instru-
ment
input
impedance
to
the
coax
characteristic
and
generator output
impedance,
thereby
minimizing
signal reflection or
power
loss
on the
line
due to im-
pedance mismatch.
The
input
and
output
impedances
of the generator
connectors are
listed
below
3-2