Crystal quartz crystal oscillator circuit using FET

A crystal oscillator operates at a frequency of 51 MHz, which corresponds to the third harmonic of a 17 MHz fundamental frequency. Depending on the specific structure used, the drain-gate capacitance can be selected within a range of 0.5 to 1.8 pF. The number of turns in inductor L2 is approximately 20% of that in inductor L1. A 470 Ω source resistor can modify the oscillation characteristics of the circuit.

The crystal oscillator circuit utilizes a crystal that resonates at 51 MHz, leveraging the properties of the third harmonic of a lower frequency crystal. This design choice is beneficial for applications requiring precise frequency generation with minimal phase noise. The oscillation frequency is determined not only by the crystal but also by the external components connected to the oscillator circuit.

The drain-gate capacitance, selectable between 0.5 pF and 1.8 pF, plays a crucial role in setting the oscillation frequency and stability. This capacitance can be adjusted based on the desired performance characteristics of the oscillator, allowing for fine-tuning of the circuit's response to variations in temperature and supply voltage.

Inductor L1 serves as the primary inductor in the oscillator circuit, while L2, with its turns ratio being about 20% of L1, acts as a coupling or feedback inductor. This configuration helps to maintain the desired oscillation conditions while also influencing the overall inductance and resonant frequency of the circuit.

The inclusion of a 470 Ω source resistor is significant as it affects the gain and stability of the oscillator. By altering the feedback network, this resistor can change the amplitude of the oscillations, thereby impacting the overall performance of the oscillator. Adjusting this resistor allows for optimization of the oscillation characteristics, ensuring reliable operation within the intended application.

Overall, this crystal oscillator design is suitable for a variety of electronic applications, including communication systems, clock generation, and frequency synthesis, where precise timing and frequency stability are paramount.Crystal oscillator works as 51MHz crystal( the third harmonic of 17MHz). According to the different structures, the drain - gate capacitance can be selected between 0.5 to 1.8 pF. L2`s turns are about 20% of the L1. 470 ? source resistor can change the oscillation characteristics.. 🔗 External reference