Icom IC-725 Instruction Manual page 18

PRE-OPERATION 4
4-5 TRANSMITTER CONTROLS
AND SWITCH
SPLIT SWITCH
For transmitting on one frequency and receiving on
another. See detailed information on p. 21.
TRANSMIT/ALC INDICATOR |
Lights up when transmitting. Lighting intensity depends
on the mic gain and your voice level. See MIC GAIN
control information below.
КЫСЫ
—
==
TUNER (Func
C3 CJ
FM ТОМЕ
RF POWER CONTROL
Varies the RF output power from 10 W to maximum.
Adjust this control for the desired output power level.
Maximum output power
• 558 : 100 W PEP
• СМ, FM : 100 W
e AM : 40W
(AM and FM operations require the optional Ul-7 AM • FM
UNIT.)
MIC GAIN
Used for adjusting the mic gain. Adjust this control to the
point where the ALC indicator lights up at its brightest level
while speaking into the mic using your normal voice level.
See ALC INDICATOR information above.
the limit of linearity, the linear amplifier outputs
Q: What is ALC? distorted signals because the signal is amplified ina
non-linear area of the signal.
A: ALC means Automatic Level Control. The ALC
circuit limits output power by controlling the input To prevent transmitting distorted signals, the ALC
level of the RF power amplifier. circuit detects a signal and applies it to a driver
amplifier as feedback to reduce driver output power.
The RF power amplifier is designed as a linear
amplifier to amplify an input signal proportionally. Therefore, the input signal level to the RF power
The linear amplifier functions in the linear area of amplifier is reduced and the transceiver transmits
clear signals.
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