User's Manual

12 68P80801H45-1 1/20/2002
Power Amplifier (PA) EBTS System Manual - Vol 2
PA Theory of Operation
900 QUAD PA
The Linear Driver Module (LDM) amplifies the low-level RF signal from the
Exciter. The LDM consists of a three stage, cascaded, Class AB amplifier, with the
final stage in a parallel configuration.
See Table 2 for the approximate input and output power of the 900 MHz QUAD
LDM.
The LDM Output is fed to the RF Splitter/DC Distribution Board via the
Interconnect Board.
Interconnect Board (40W-800 MHz, 70W-800 MHz , 800 MHz QUAD
and 900 MHz QUAD)
The output of the LDM is applied to the Interconnect Board, which provides an
RF connection to the RF Splitter/DC Distribution Board. As a separate function,
area on the Interconnect Board serves as a convenient mounting location for
electrolytic capacitors used for filtering the +28 VDC supply.
RF Splitter/DC Distribution Board
40W-800 MHz, 70W-800 MHz, 800 MHz QUAD and 900 MHz QUAD
The RF Splitter portion of this board accepts the amplified signal from the LDM
(via the Interconnect Board). The primary function of this circuit is to split the RF
signal into drive signals for the LFMs.
In the 40W-800 MHz PA, this circuit splits the drive signal into three separate
paths to be applied to the three LFMs, where the signals will be amplified further.
In the 70W-800 MHz, 800 MHz QUAD and 900 MHZ QUAD PAs, this circuit
splits the drive signal into six separate paths to be applied to the six LFMs, where
the signals will be amplified further.
The DC Distribution portion of this board interfaces directly with the DC/
Metering Board to route DC power to the LFMs and provide PA Bias Enable (900
MHz QUAD only)
900 MHz and 1500 MHz
The RF Splitter portion of this board accepts the amplified signal from the LDM.
The primary function of this circuit is to split the RF signal into two separate
paths. These two outputs are fed directly to two separate Linear Final modules
where the RF signals will be amplified further.
The DC Distribution portion of this board interfaces directly with the DC/
Metering Board to route DC power to the LFMs.