9/15/06
888-2586-001
4-51
WARNING: Disconnect primary power prior to servicing.
Section 4 Overall System Theory
Platinum Z16HD+
c.
Strike 3 - A third fault detected within this 10 seconds will cause the transmitter
to be muted until the operator gives the transmitter an ON command (High or
Low), locally or by remote. If the cause of the fault is still present, the transmitter
will simply repeat the 3 strikes and mute again.
NOTE:
If no faults occur during either of the 10 second time periods, then the strike
counter is reset and will allow 3 more strikes before muting the transmitter.
The slow ramp up in power after a strike should allow the foldback controls to limit the
transmitter power output before the fault thresholds are reached again. The slow power
ramps are designed to allow the transmitter to operate at the maximum possible power
level without over-dissipating the isolation resistors or exposing the transmitter to
excessive reflected power. This would mean that there would be a fault in the log but it
would be inactive and the transmitter would be in a foldback condition.
4.8.5
PA Controller Boards
There are four (4) PA Controller Boards in the Z16HD+ transmitter. They utilize micro-
controllers which report to the Master Controller, but operate independently of the
Master. Each controls 8 of the 32 PAs. Table 4-1 shows which PAs are controlled by
each of the PA Controller Boards. The boards are identical except for the programmable
ID number which is set with DIP switches on the board to determine which board is PA
Controller 1, 2, 3 or 4.
The PA Controllers are responsible for the following:
•
Turn on/Turn off of the PAs via the PA gate bias voltage.
•
Metering, status and fault monitoring of the PAs and the isolation resistors associated
with them.
•
Control of the combiner isolation switches (located on the isolation boards) which
are associated with the PAs under its control.
•
Crossover protection (the ability to mute the PAs which are controlled by another PA
Controller Board in case of a failure).
4.8.5.1
PA Turn On/Turn Off
The PA Controllers primary responsibility is to turn the PAs on and off. The PAs are
turned on and off by varying the voltage on the gates of the MOSFETs on the PAs. If the
gate voltage is 0V, the PA is turned on full. If the gate voltage is -18V, then the PA is
turned off. This means the PA Controllers have the ability to turn off or MUTE each PA
individually, or all at the same time if it is necessary to MUTE the entire transmitter RF
output.
Summary of Contents for Platinum Z16HD+
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