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8
DC
OFFSET
Control - Offsets the
waveforms or gives dc levels from -10V to
+ 10V (- 5V to + 5V into
-1V to + 1V (- 0.5V to + 0. 5V into 500) at
11
. An OFF position ensures no offset.
9
AMPLITUDE
Control - Ccw rotation reduces
waveform amplitudes at
30 dB. DC and offset voltages are not affected
by this control.
10
SOD OUT HI
Connector - The main output of
the generator at the function selected. Maximum
20V p-p
V p-p into
(1 O
SOD)
amplitude control. 500 source impedance.
11
500
Connector - Same as
OUT LO
cept 20 dB (1/10) lower in amplitude.
12
TIL 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.
13
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.
14
VCG
IN
Connector - Accepts ac or dc voltages
to proportionately control frequency within the
range
determined
by
MULTIPLIER
. Positive voltage increases the
3
frequency set by the dial
decreases the frequency. The VCG IN will not
drive the generator frequency beyond the nor
mal dial limits of a range. Input impedance is
21<0.
3.2
OPERATION
Perform the initial checkout in Section 2 for the feel of
the instrument. Any questions concerning Individual
controls
and
connectors
paragraph 3.1.
Signal Termination
3.2.1
Proper signal termination, or loading, of the generator
connectors is necessary for its specified operation.
For example, the proper termination of either of the
OUT connectors is shown in figure 3-2. Placing
SOD
the
50 ohm terminator, or 50 ohm resistance, in
parallel with a higher impedance, matches the receiv
ing
instrument
input
impedance
characteristic
and
generator
thereby minimizing signal reflection or power loss on
the line due to impedance mismatch.
The input and output impedances of the generator
connectors are listed below.
3-2
SOD
OUT
SOD)
at
10
and from
10
and
11
by
with 30 dB continuous
ex
10
the
FREQUENCY
; negative voltage
1
may
be
answered
in
to
the
coax
output impedance,
Connector
500 OUT
(H
I) ............................. 500
500 OUT (LO) ............................. 500
SYNC OUT (TTL) .. : ......................... *
TRIG IN ................................... *
VCG IN ................................. 2 kD
* The TTL OUT connector is diode protected and can
drive up to 20 Transistor-Transistor-Logic (TTL) loads
(low level between OV and 0.4V, and high level bet
ween 2.4V and 5V). It should not be conencted to
resistive load less than 6000. The TRIG IN connector
accepts TTL logic levels, is diode protected, and re
quires 500 pA drive from a high level output.
MODEL 182A
OUTPUT
IMPEDANCE
500
Figure
3·2.
Signal Tennlnatlon
Manual Function Generator Operation
3.2.2
For basic operation, select the waveform frequency
and amplitude. The following steps demonstrate
manual control of the function generator. (Bold
numbers are keys to figure 3-1.)
Step Control/Connector
OUT
SOD
10
11
Connect circuit to either
output
graph 3.2.1).
2
FREQUENCY
Set to desired range of fre
MULTIPLIER
3
quency.
3
Frequency Dial
1
Set to desired frequency
within the range.
4
FUNCTION 7
Set to desired waveform.
5
DC OFFSET
8
Set as desired. Limit wave
form amplitude to prevent
clipping (see figure 3-3).
6
AMPLITUDE 9
Select for desired ampli
tude.
Impedance
RECEIVING
INSTRUMENT
EFFECTIVE
CIRCUIT
RESISTANCE
(SIGNAL
LOAD)
.500
Setting
(refer
to
para
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