4-12
888-2586-001
9/15/06
WARNING: Disconnect primary power prior to servicing.
Platinum Z16HD+
Section 4 Overall System Theory
4.4.2.1
Manual IPA Switching
The on-air IPA pair can be selected manually using the Diagnostics Display. The IPA
select screen is located in the IPA Status menu. For exact location, refer to the
“Diagnostics Display Menu Tree” drawing in the schematic package.
Figure 4-3 IPA Status and Manual Switch Screen
[HOME, STATUS, A, C]
4.4.2.2
IPA Power Output
In any modulation format using an HDx-FM exciter and/or BoostPro, the IPA is a 19dB
fixed gain class A/B amplifier that is held fully on unless a mute condition exists.
In the Backup FM (analog exciter) mode, the variable APC voltage is applied to the IPA
gates for power level control.
The gate bias voltage range is about -18V for off and 0V for full on.
4.4.2.3
IPA Power Supply
The IPA power supply is +52 volts and is diode OR’ed from two of the four PA power
supplies for redundancy. The +52Vdc is connected to the IPAs via the IPA Backplane
Boards. IPA_AB1/AB2 are powered from PS1 and PS2 while IPA_CD1/CD2 are
powered by PS3 and PS4. The supply feeds for the IPAs are diode or’ed together on the
Rectifier Boards before going to the IPA Backplane Boards. This provides added
protection against the loss of one supply.
4.4.2.4
IPA Backplane Boards
Refer to the IPA Backplane schematic for the following. Keep in mind that “IPA
Backplane for IPA_AB” is identical to “IPA Backplane for IPA_CD”, therefore only
IPA Backplane IPA_AB will be discussed here. The RF input to the IPA Backplane
board is J3. RF Switch K1 is not used for either configuration of this board in the
Z16HD+ transmitter (note that this board is also used as the Exciter Divider).
Summary of Contents for Platinum Z16HD+
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