4.1 - 4 THEORY OF OPERATION (TRANSCEIVER)
Frequency Generating Section
The frequency generating section comprises the following components:
• Reference Oscillator - TCXO
• Main Synthesizer - consists of the Main Voltage Controlled Oscillator (VCO) and Low Voltage
Fractional-N integrated circuit (LVFRACN). In receive mode, the main synthesizer provides
the local oscillator injection to the receiver first mixer. In transmit mode, this synthesizer
provides the frequency reference for the transmit frequency translation loop.
• Transmit frequency translation loop. Consists of the transmit Voltage Controlled Oscillator
(VCO) and ESCORT Near Unity Divider (NUD) Phase Locked Loop IC.
GPS Section
The GPS Sub module includes the following main components:
• Front End Filter
• LNA matching network
• The Phoenix GPS Acquisition Module (PGAM)
• 26MHz Reference TCXO
• Power supply for PGAM IC
• 5V (20mA) Phantom Power Supply for external LNA
6866539D31.book Page 4 Tuesday, March 20, 2007 6:32 PM
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