© 2001 – Ericsson Amplifier Technologies Inc.
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4.7.2
Standby
Mode:
(All LEDs off)
The MCPA has not had the DC power switch pressed and is not biased on. Low level
communication ( e.g. between the subrack and amplifier) is enabled.
4.7.3
DC On
Mode
(DC Switch LED – ON)
The front panel DC on switch has been depressed, and the integral LED indicator is
illuminated. When used with the Ericsson Amplifier Technologies subrack, the subrack
acknowledges the initial operation of the module and configures the subrack to insert
the module into the combining circuit, provided the module does not indicate an alarm
which would shutdown the module. Thus the module system will reconfigure itself
automatically as the additional modules are (DC) powered-up, to effectively use the
new module.
4.7.4
Enable
Mode
(DC Switch and Enable LED – ON)
The MCPA is amplifying the signal. (When used with Ericsson Amplifier Technologies
subrack, all power is being combined.)
4.7.5
Shutdown
Mode
Any of these LEDs ON: VSWR, OVER PWR, TEMP/WARN, LOOP or PWR SPLY
The MCPA amplifier has turned itself off for protection. All alarm indications are
latched, and the amplifier is shutdown. The amplifier can be reset by pressing the DC
switch. If the alarm still exists, the amplifier will re-enter the shutdown mode.
4.7.6
ALC
Mode
(Blinking OVER PWR LED)
The module supports power limiting to mitigate an overdrive condition. When the
OVER PWR LED blinks, the module has entered the ALC mode. In the ALC mode, the
module limits the maximum transmit power to 0.5 dB above nominal output power by
reducing the gain of the MCPA. The gain of the MCPA is continuously adjusted to
maintain this limited value. If the loop circuits can no longer maintain the limited value
due to excessive input power, the MCPA will protected itself by shutting down and
indicate a overdrive condition with a steady OVER PWR LED indication. After 30
seconds, the MCPA will turn back on in the minimum gain setting, and attempt to limit
power once again.
If the power is still too high during the subsequent attempt, the module will overdrive
again and shutdown. The re-enable sequence will be performed three times before the
module remains shutdown, and will require re-initialization (power up sequence) in
order to reset.
