Uncompromising Connectivity.
The Pure-Core Architecture: Engineering Silence
The heart of the OL-SDR lies in a motherboard designed with a philosophy of absolute functional isolation. Unlike conventional integrated designs, we have chosen to keep the core electronics separate from the front-end, amplification, and power supply modules. This discrete block structure is the key to achieving an artifact-free signal and a noise floor approaching the theoretical zero.
Motherboard Technical Highlights:
The Digital Engine: Processing power is driven by the Efinix Titanium FPGA. This cutting-edge choice ensures massive computational power and ultra-low latency, managing data streams with precision unattainable by standard processors.
Galvanic & RF Separation: The Ethernet section and audio interfaces are strictly isolated from the primary signal path. This prevents electromagnetic coupling or digital jitter that could degrade reception purity.
Integrated LPF Filtering: The board features high-quality Low-Pass Filters (LPF), strategically positioned to clean the signal during the primary processing stage, before it even reaches the external amplification stages.
Signal Purity: By keeping critical components (such as power supplies and TX filters) off the motherboard, we have created an "electronically silent" environment. The result is a signal dynamic range and in-band discrimination capability that place the OL-SDR at the pinnacle of global performance.
High-End Components: The Choice of Excellence
A pure architecture demands superior components. For the OL-SDR, we rejected cheap integrated solutions in favor of the world’s finest discrete components, ensuring stability, purity, and dynamic range under any operating condition.
The Pillars of Precision:
Ultra-Stable Frequency Reference: The use of Crystek oscillators (such as the CVPD-922X) guarantees a clock with extremely low phase noise. This precision is vital for signal stability in digital modes and ensures crystal-clear reception.
Professional Mini-Circuits® Filtering: The motherboard features shielded Mini-Circuits Low-Pass Filters (LPF). These components are the RF industry standard for suppressing harmonics and spurious signals with minimal insertion loss.
Noise-Free Signal Management: Every inductor, capacitor, and relay on our boards is selected for its linearity. This approach prevents thermal noise and intermodulation, preserving the full dynamic range offered by the Efinix Titanium FPGA.
Military-Grade Build Standard: The quality of the soldering, the gold-plated trace routing, and the component layout highlight a meticulous obsession with Signal Integrity. Every section is engineered to endure, even under intense and continuous duty cycles.
Our system delivers approximately 70dB of attenuation (combined with RX band filters, typically >40dB) against FM Broadcasting frequencies (88-108MHz). This dual-stage filtering prevents interference within the 15-35 MHz range, ensuring a clean and artifact-free spectrum even in challenging RF environments. By effectively suppressing out-of-band signals, the architecture prevents ADC front-end overload, preserving the full 107dB RMDR and ensuring that weak signals remain perfectly readable even in the presence of high-power local transmitters.
TCXO (Temperature Compensated Crystal Oscillator): Our system features a high-stability reference with an accuracy of ±50 ppb (0.5Hz at 10MHz) across the entire operating temperature range (0°C to 70°C). This ensures unwavering frequency stability even during intensive operations.
GNSS Discipline Input: Includes a dedicated antenna input for GNSS (GPS, GLONASS, Galileo). This allows the system to be disciplined by global satellite constellations for absolute frequency accuracy and long-term stability (GPSDO functionality).
Ultra-Low Noise Oscillator: Dedicated clocking for ADC, DAC, and FPGA with a typical phase noise of -155dBc/Hz @ 10kHz offset. This extreme purity is the foundation of the system's superior dynamic range.
Direct Differential Drive: The LVPECL output drives the RX ADCs, the TX DAC, and the FPGA via matched differential lines. By eliminating intermediate active components, we ensure the highest possible RF performance and maintain total signal integrity across the entire digital chain.
Front-End Preselector: The First Line of Defense
Exceptional reception in an SDR system depends on more than just software; it relies on the hardware's ability to manage hostile signals before they are even digitized. Our Front-End Filter Board is a masterpiece of analog engineering, designed to isolate the desired signal in even the highest-density spectral environments.
Technical Architecture & Advantages:
Mechanical Switching Architecture: The use of an extensive array of high-quality relays allows for the selection of physically separated filter paths. This ensures a level of inter-band isolation that low-cost electronic switches simply cannot achieve.
High-Selectivity Passive Preselection: The board acts as a mechanical sieve, eliminating out-of-band signals (BCI, strong adjacent broadcasters) that would otherwise cause receiver saturation or desensitization.
Dynamic Range Protection: By filtering the signal before the ADC stage, we preserve the full dynamic range of the Efinix Titanium FPGA, enabling you to pull weak signals out of the noise even when positioned right next to extremely strong interference.
Signal Integrity & Low Loss: The component layout is meticulously optimized to minimize insertion loss and keep the noise floor at the lowest possible physical levels.
Pure Signal Technology: Surgical Transmission Accuracy
Transmission excellence doesn't end at the radio's output. The Pure Signal technology integrated into the OL-SDR ecosystem is engineered to deliver unprecedented signal linearity, eliminating intermodulation distortion (IMD) at its source.
Adaptive External Feedback
Unlike conventional systems, the OL-SDR hardware features a dedicated input port (PS IN) for real-time signal sampling.
Post-Amplification Analysis:
The system analyzes the signal sampled directly from the output of an external linear amplifier or post-radio power stages.
Predictive Correction:
Utilizing a Digital Pre-Distortion (DPD) algorithm processed by the Efinix Titanium FPGA, the system compares the original signal with the output, instantaneously correcting any non-linearity introduced by the power chain.
Total Spectral Purity:
The result is a "surgical" transmission with drastically suppressed sidebands. This clean signal ensures no interference with adjacent frequencies, maximizing both energy efficiency and effective range.
Technical Specifications
OL-Master
