User's Manual

14 68P80801H45-1 1/20/2002
Base Radio Exciter EBTS System Manual - Vol 2
QUAD Channel 900 MHz Exciter
90.3 MHz Voltage Controlled Oscillator (VCO)
The synthesizer within the Low Noise IC sets the 90.3 MHz signal. The 90.3 MHz
VCO provides a LO signal to the LNODCT IC. The Low Noise IC uses this signal
in up-converting and down-converting the feedback signal.
Regulator Circuitry
The voltage regulators generate three regulated voltages: +3 Vdc, +5 Vdc and
+11.7 Vdc. The regulators obtain input voltages from the +3.3 Vdc and +14.2 Vdc
backplane voltages. The regulated voltages power various ICs and RF devices in
the Exciter.
Linear RF Amplifier Stages
The linear RF amplifiers boost the RF signal from the Low Noise IC. The RF
Amplifier generates an appropriate signal level to drive the PA.