Wavetek 188 - Operation

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