Design and Realization of Direct PLL FM Transmitter for UAV Data Link

Based on the UAV requirements of small airborne equipment, the paper discusses the necessity of using PCM-FM modulation method to design small airborne transmitter. It is also introduced the principle to complete transmitter design using direct PLL FM technology, given phase transmission model using of dual voltage-controlled ports of the VCO to achieve direct PLL FM and PLL circuit design. Simulation and experimental data are close to the theoretical analysis, and further flight application shows that airborne transmitter using the direct PLL FM not only small but also is able to meet the high-speed data transmission requirements.