Soft Decision Analyzer
Soft Decision Analyzer (MSC-TOPS-61)
Detects Bit Slips for RF Receiver Data Quality
Innovators at NASAs Johnson Space Center have developed the Soft Decision Analyzer (SDA) to conduct real-time, closed-loop statistical analysis of a radio frequency (RF) receiver system in a variety of operating conditions. Comprised of hardware, firmware, and software, the instrument monitors and analyzes data loss known as bit slip. This can be caused when a transmitter with a higher clock-rate overwhelms a receiver with a lower clock-rate and exceeds its data buffering, there are low signal to noise conditions, or a situation induces an RF channel assignment swap. The Soft Decision Analyzer is a TRL 6 (system/subsystem prototype demonstration in a relevant environment) and it is now available for your company to license and develop into a commercial product. Please note that NASA does not manufacture products itself for commercial sale.
The Soft Decision Analyzers (SDA) closed-loop data detection allows it to measure real-time correlation observations with frame, codeword, and packet losses, as well as quality of service (QoS) and quality of experience (QoE) events. The SDA incorporates two techniques for identifying bit slips. The first is an examination of the received data stream's relation to the transmitted data content. The second is a direct examination of the receiver's recovered clock signals relative to a reference. Using these two techniques allow for a better understanding of receiver performance in this regard. The SDA detects receiver bit slips within a +/- 4-bit window and offers continuous four-quadrant tracking for multiple modulation schemes and signal-to-noise ratio measurements using techniques that work even in the presence of symbol-clipping. It continuously monitors correlation results to characterize slips and quadrant change and is capable of performing analysis even when the receiver being tested is subjected to high error-rate conditions (30 percent or beyond). The SDA also incorporates a watchdog trigger that permits the system to automatically recover from large receiver upsets while continuing its performance analysis.
- Provides flexible data correlation with continuous quadrant monitoring in either developmental or operational environments to combat bit slip
- Offers wide-ranging soft decision statistical measurements and early error detection
- Extensible: Publishes data output in a spreadsheet or extensible markup language (XML) format, allowing for easy organization and rapid results presentation
- Any commercial, military, or aerospace field needing to identify and address quality of service and quality of experience issues with RF communication receiver systems