The Core Application of Crystal Oscillators in FTTR Systems: An Analysis of Taijing Technology's High-Frequency Low-Noise Solutions
In recent years, the telecommunications industry has continuously accelerated the upgrade of optical bandwidth. The continuous improvement of network infrastructure, such as optical access, has brought convenience to our lives. Meanwhile, innovative commercial applications are also increasing, such as ultra-high-definition video, cloud VR, cloud gaming, and online education, which impose ever higher demands on network bandwidth, latency, and jitter. FTTR has thus emerged accordingly.
FTTR (Fiber to the Room) delivers gigabit broadband directly to every room via a single fiber optic cable, making it one of the most popular technical approaches for "true whole-home gigabit coverage." After entering the premises, the fiber optic cable converts optical signals into high-speed data through an optical line terminal (OLT) and optical network unit (ONU/gateway), which is then distributed to terminals like mobile phones, computers, and TVs. To ensure these devices operate in perfect synchronization at high speeds, a precise, stable, and low-noise "heart"—a crystal oscillator—is essential.
The Application of Crystal Oscillators in FTTR
In the FTTR system, crystal oscillator products serve as core components of electronic devices, playing a crucial role. They are primarily used in OLT and ONU equipment to provide precise clock signals. These clock signals are the foundation for the synchronized operation of various functional modules within the devices, ensuring the accuracy and stability of data transmission.
Provide public heartbeat
The OLT and ONU contain multiple modules such as switching chips, network processors, and Wi-Fi basebands, all of which must operate in sync under the same clock signal. The crystal oscillator serves as the "commander," outputting a precise reference clock to prevent data loss or collisions.
Decide "how fast to run"
To achieve speeds of 1 Gbps or even 10 Gbps with FTTR, the system clock frequency often needs to reach 50 MHz to 156 MHz or higher. High-frequency crystal oscillators (above 100 MHz) thus become standard, enabling faster data transmission.
Ensure "stability"
When the frequency fluctuates, the network connection drops. High-stability crystal oscillators ensure long-term consistency of clock signals, while temperature-compensated crystal oscillators (TCXO) or oven-controlled crystal oscillators (OCXO) can reduce thermal drift to ±0.1 ppm, minimizing communication errors caused by frequency drift.
Noise reduction and anti-shake
High-speed SerDes and PON ports are extremely sensitive to clock jitter. The use of low-phase-noise and low-jitter crystal oscillators helps improve the overall network performance and user experience.
Miniaturization and energy conservation
In the FTTR system, using small-sized and low-power crystal oscillator products not only meets design requirements, but also helps to improve the overall performance of the system.
Four key words of Taijing crystal oscillator
High frequency: above 100 MHz, meeting the clock requirements of 10 Gigabit fiber optic networks.
Low noise: 156.25MHz high-frequency oscillator phase noise<-165 dBc/Hz @ 1 MHz offset, jitter<60 fs.
Temperature compensation: High precision temperature compensated crystal oscillator, with frequency drift<± 0.1 ppm throughout the temperature range of -40 ℃ to+105 ℃.
Small size: The product's external dimensions range from 1.6mm × 1.2mm to 5.0mm × 3.2mm in various packages, suitable for different motherboard layouts.
If FTTR is compared to an information highway, fiber optic cables are wide lanes, and crystal oscillators are traffic lights and signs - they may not be visible, but they determine whether data packets can arrive on time. As FTTR evolves towards 10G, 50G, and even higher, crystal oscillators will continue to upgrade towards higher frequencies, lower noise, smaller sizes, and full temperature compensation, safeguarding the gigabit experience for thousands of households.
