The **FTS-21-R** is an electronic component primarily classified as a **Precision Temperature-Compensated Crystal Oscillator (TCXO)** or a specialized **Frequency/Time Source module**. These parts are designed for high-stability timing applications where standard oscillators would fail due to temperature fluctuations. --- ### 1. Key Technical Specifications The following table outlines the typical electrical and mechanical characteristics of the FTS-21-R series: | Feature | Specification | | :--- | :--- | | **Component Type** | Temperature-Compensated Crystal Oscillator (TCXO) | | **Output Frequency** | Usually 10.0 MHz (standard for timing) | | **Stability** | $\pm 0.1$ ppm to $\pm 1.0$ ppm (depending on temp range) | | **Supply Voltage** | Typically 5V DC or 3.3V DC | | **Package Style** | Through-hole or ruggedized metal can | | **Operating Temp** | -40°C to +85°C (Industrial Grade) | --- ### 2. Core Electronic Architecture The "R" suffix often denotes a **Ruggedized** or **RoHS-compliant** version. The internal electronics consist of three main stages: 1. **Crystal Resonator:** A precision-cut quartz crystal that vibrates at a specific frequency. 2. **Compensation Network:** A thermistor-based circuit or a digital compensation IC (DCXO) that senses ambient temperature and adjusts the load capacitance to keep the crystal on-frequency. 3. **Output Buffer:** An electronic stage (usually CMOS or Sine Wave) that ensures the signal can drive other components without degrading the frequency stability. --- ### 3. Applications Because of its high precision, the FTS-21-R is commonly found in the following systems: * **GPS/GNSS Receivers:** Providing the local clock reference for satellite signal acquisition. * **Base Stations:** Synchronizing cellular data packets in telecommunications. * **Test & Measurement:** Used as a reference clock in frequency counters or signal generators. * **Tactical Radio:** Ensuring stable communication in environments with extreme temperature swings. --- ### 4. Implementation Example If you are integrating this into a circuit, the pinout generally follows this standard logic: ```c Pin 1: Vc (Voltage Control/Tuning - Optional) Pin 7: Ground (GND) Pin 8: Output (Clock Signal) Pin 14: Vcc (Supply Voltage) ```