The **FTS-15-R/Q** typically refers to a high-precision, space-grade **Quartz Crystal Oscillator** or a similar frequency timing standard component, often associated with manufacturers specializing in high-reliability timing (like the former Frequency Time Systems, now part of Microchip/Microsemi). Below is an explanation of its electronic components and characteristics. --- ### 1. Component Overview The FTS-15 series is designed for applications requiring extreme stability, such as satellite communications, GPS synchronization, and aerospace telemetry. | Feature | Specification Detail | | :--- | :--- | | **Component Type** | Oven Controlled Crystal Oscillator (OCXO) | | **Frequency Range** | Typically 5 MHz to 20 MHz (Model dependent) | | **Stability** | Parts-per-billion (ppb) range | | **Input Voltage** | Usually +12V or +15V DC | | **Output Type** | Sine wave or HCMOS/TTL | --- ### 2. Key Internal Electronic Parts The "R/Q" designation usually points to specific radiation hardening (R) or qualification levels (Q) for space environments. The internal architecture consists of: #### A. The Quartz Crystal (The Resonator) * **SC-Cut Crystal:** Most high-end units use a "Stress Compensated" cut crystal, which is less sensitive to mechanical and thermal shock than standard AT-cut crystals. * **Aging Control:** The crystal is "swept" to remove impurities, ensuring the frequency doesn't drift significantly over years of operation. #### B. The Oven Control Circuitry To achieve high stability, the crystal is placed inside a thermally regulated "oven." * **Thermistor:** Acts as the temperature sensor. * **Heating Element:** A power transistor or resistor used to maintain a constant internal temperature (usually around 75°C to 85°C). * **Control Loop:** An analog or digital proportional controller that balances the heat to counteract external ambient temperature changes. #### C. The Oscillator Circuit * **Varactor Diode:** Used for electronic frequency tuning (EFC). By changing the voltage to this diode, the capacitance changes, allowing for minute adjustments to the output frequency. * **Buffer Amplifier:** Isolates the crystal oscillator from the output load to prevent "load pulling" (frequency shifts caused by changes in the external circuit). --- ### 3. "R/Q" Designator Significance In the context of high-reliability electronics: 1. **"R" (Radiation Hardened):** Indicates the internal semiconductors (transistors, op-amps) are designed to withstand Total Ionizing Dose (TID) and Single Event Effects (SEE) from cosmic radiation. 2. **"Q" (Qualified/Space Grade):** Indicates the part has undergone rigorous screening, including "burn-in" periods, vibration testing, and thermal vacuum cycling to ensure it won't fail once launched. --- ### 4. Pinout and Interface (General) While specific footprints vary, these modules generally follow a standard header: ```text Pin 1: Supply Voltage (Vcc) Pin 2: RF Output (Sine or Square) Pin 3: Ground (Case) Pin 4: Electronic Frequency Control (EFC) / Control Voltage Pin 5: Reference Voltage Output (Vref) ``` ---