User's Manual

3. CIRCUIT DESCRIPTION
TRANSMITTER
The transmitter is comprised of:
• Audio amplifier connections from J902 pin 1
• Frequency Synthesizer
• Transmitter
• Automatic Power Control
Audio frequency connections
Processed data from the IC504 is applied to the VCO via R316
and applied to the TCXO VC
Frequency synthesizer circuit
With data received from the EEPROM (IC5) the frequency synthesizer circuit controls and
Produces the RF carrier frequency for the transmitter during transmit and the local oscillator
frequency for the receiver. The frequency synthesizer circuit is comprised of:
• 12.8 MHZ Tcxo
• Voltage Controlled Oscillator (VCO) module
• Charge Pump and Loop Filter
• PLL Frequency Synthesizer
• Dual Modulus Prescaler
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