The **REB-C4-R/Q** is a high-performance **GPS/GNSS Receiver Module** (specifically from the RoyalTek REB series). These modules are designed for integration into embedded systems, vehicle tracking devices, and handheld electronics. The "R/Q" designation usually refers to specific hardware revisions or interface protocols (like TTL or RS232 levels) and packaging types (Roll/Tape or Bulk). --- ## 1. Key Electronic Specifications The performance of the REB-C4 is driven by its internal chipset architecture (typically based on SiRFstarIV or similar high-sensitivity technology). | Parameter | Specification (Typical) | | :--- | :--- | | **Chipset** | High-performance GNSS Engine | | **Channels** | 48+ Tracking Channels | | **Supply Voltage (VCC)** | 1.75V to 1.9V (Internal core) / 3.0V to 3.6V (I/O) | | **Power Consumption** | ~35mA to 45mA (Tracking mode) | | **Sensitivity** | -163 dBm (Tracking) / -148 dBm (Cold Start) | | **Interface** | UART (Universal Asynchronous Receiver/Transmitter) | | **Update Rate** | 1 Hz to 5 Hz | --- ## 2. Main Internal Components The module is a "System in Package" (SiP) consisting of several critical electronic sections: ### A. The GNSS Processor The brain of the module. It handles signal correlation, position calculation (Latitude, Longitude, Altitude), and time synchronization. It processes the NMEA-0183 protocol messages. ### B. Low Noise Amplifier (LNA) A built-in LNA is used to amplify the very weak signals received from the GPS satellites (approx. -130dBm at the antenna) before they reach the RF down-converter. ### C. SAW Filter (Surface Acoustic Wave) This component filters out electromagnetic interference (EMI) from nearby cellular signals (LTE/GSM) or Wi-Fi, ensuring only the GPS frequency band (1575.42 MHz) is processed. ### D. TCXO (Temperature Compensated Crystal Oscillator) Essential for frequency stability. It ensures the module can lock onto satellite signals quickly, even in extreme temperature variations (-40°C to +85°C). ### E. Real-Time Clock (RTC) & Backup Battery Pin The module includes a pin for a backup battery (VBAT). This allows the module to store "Ephemeris" data, enabling a **Hot Start** (acquisition in <1 second) after being powered down. --- ## 3. Pinout & Connectivity Layout The REB-C4 usually utilizes a SMT (Surface Mount Technology) pad layout. | Pin Name | Function | Description | | :--- | :--- | :--- | | **VCC** | Power Input | Main DC power supply. | | **GND** | Ground | Common system ground. | | **TX** | Data Out | Transmits NMEA data to the Microcontroller (MCU). | | **RX** | Data In | Receives configuration commands from the MCU. | | **1PPS** | Pulse Per Second | High-precision time pulse for synchronization. | | **RESET** | System Reset | Active low pin to restart the module. | --- ## 4. Integration Requirements To use the REB-C4-R/Q in a circuit, engineers must provide: 1. **Antenna:** A passive or active 50-ohm ceramic patch antenna. 2. **Decoupling Capacitors:** Usually 10uF and 0.1uF near the VCC pin to filter power noise. 3. **Level Shifters:** If the MCU operates at 5V, level shifting is required as the REB-C4 operates at 3.3V logic.