User's Manual

3. CIRCUIT DESCRIPTION
TRANSMITTER
The transmitter is comprised of:
• Audio amplifier connections from J501 pin 1
• Frequency Synthesizer
• Transmitter
• Automatic Power Control
Audio frequency connections
Processed data from the IC504 is applied to the VCO via P305 and applied to the TCXO
P701
Frequency synthesizer circuit
With data received from the EEPROM (IC502) 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
PAGE 4