CHAPTE
OPERATI
3.1 FUNCTIONAL DESCRIPTION
The ENI Model 3100LA ts alinear Class Aamplifier
capable of Increasing the output of any sigrai gener-
ator, frequency synthesizer, sweep generator or labor-
atory signal source from 250 kHz to 150 MHz.
The Model 3100LA is completely protected against
dantage due to load mismatch provided dat the input
RF level does not exceed 1volt RMS or 1.4 volts p^k.
If the attached signal source Is capable of generating
substantially more than this input voltage, please use
caution in adjusting it. The Model 3100 LA will
saturate well before the maximum input voltage and
there will be no increase in output power at that point.
The 3100LA is unconditionally stable. Any
impedance can be connected to the input and output
of the amplifier, without causing oscillation,
The 3100 LA will deliver its rated power to any load
impedance regardless of match. Load mismatch will
cause RF power to reflect back to the amplifier. The
unit is designed to withstand 100 percent reflected
power (a pure reactance open or short circuit load will
cause 100 percent reflected power) continuously with-
out damage.
An output meter is provided to indicate the average
output voltage (calibrated in RMS) as well as the
power output when the unit is connected to a50 ohm
load. Since the meter responds only to average out-
put, the modulation characteristics of the input signal
must be taken into account when interpreting the
meter readings. For example, the amplifier may be in
saturation during the ON portion of apulse yet the
meter reading will be low due to the low duty cycle of
the pulse Input.
3.2 CONTROLS. INDICATORS AND CONNECT-
ORS
Front and roar panel devices are described in Table 3-1
.
3.3 OPERATING PROCEDURE
Refer to the following procedure as aguide to oper-
ating the Model 3100LA.
e. The input and output are connected via the front
panel type Nconr>ectors to the sigrial source and
load respectively.
b. The input signal should be increased gradually
while observing the output voltage on the output
RF voltmeter.
c. When the Model 3100LA is connected toa50
ohm load, the CW power output of the unit may
be read directly from the meter scale.
d. When the amplifier is connected to an arbitrary
or unknown load impedance, the following pro-
cedure will insure alow distortion power output.
1.Disconnect the output load cable from the
output type Nconnector of the Model 3100LA,
2. If the CW output voltage is less than 100
volts RMS, the unit is operating at low distor-
tion regardless of the load impedance.
3. Reconnect the output of the amplifier to the
load.
e. If the output of the amplifier is monitored by a
high frequency oscilloscope or spectrum analyzer,
the input signal may be increased until the point
of maximum undistoned power output is ob-
served.
3.4
PRECAUTIONS
a. The input and output of the Model 31 00 LA
should not be connected together. This will
cause oscillation ar>d may damage the input
preamplifier.
b. The Model 3100LA should not rerr>aln connected
to an antenrtf when the unit is not in use. If
thunderstorms are likely. It would be prudent to
earth grourKl the unit's case.
c. When the input signal voltage of the signal
source is unknown, insert an attenuator between
it and the Model 3100LA input.
3-1
