RDM dB Compression Using Exponent-Mantissa Lookup Conversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing telemetry systems face challenges in efficiently converting binary floating-point format range Doppler map (RDM) values into compressed decibel (dB) format for real-time transmission over telemetry links, particularly in scenarios requiring low latency and high reliability.
Innovation Solution
A telemetry device processes RDM values by determining a first number based on the product of the exponent and a constant proportional to the base-10 logarithm of 2, and a second number using the most significant bits of the mantissa as an index into a lookup table, with values proportional to base-10 logarithms of candidate mantissa values, to generate a compressed RDM value through rounding, which is then transmitted over a telemetry link.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If binary floating-point format is used for RDM values, then measurement precision is maintained, but data transmission bandwidth efficiency deteriorates
Solution Approach 1:
The patent changes the numerical representation parameter from binary floating-point format to decibel scale with fixed-point representation. This parameter transformation compresses the dynamic range of RDM values by mapping large exponential variations into a condensed logarithmic scale, reducing the number of bits required for transmission while preserving essential measurement precision through the lookup table interpolation method.
Solution Approach 2:
The patent creates a compressed representation (copy) of the original RDM values by converting them to decibel scale. The lookup table stores pre-computed decibel values that serve as efficient copies of the full-precision floating-point data, enabling bandwidth-efficient transmission while maintaining adequate precision through the copying mechanism.
2Measurement precision
If complex conversion algorithms are used to convert floating-point to dB, then conversion accuracy is improved, but processing time increases
Solution Approach 1:
The patent applies preliminary action by pre-computing and storing decibel values in a lookup table before runtime conversion is needed. The table contains pre-calculated dB values for various mantissa-exponent combinations, allowing the conversion process to simply retrieve and combine these pre-computed values rather than performing complex logarithmic calculations in real-time, thus reducing processing time while maintaining accuracy.
Solution Approach 2:
The patent segments the conversion process into independent components: extracting the exponent, extracting the mantissa, looking up pre-computed values in separate table entries, and combining results through simple addition and rounding. This segmentation of the conversion algorithm into discrete, manageable steps enables efficient parallel processing and reduces the computational complexity of the overall conversion operation.
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
Embodiments of a telemetry device and methods to convert a binary floating point number to a compressed number is described herein. The binary floating point number may comprise a mantissa and an exponent. The telemetry device may determine a first number based on a product of the exponent and a constant, wherein the constant may be proportional to a logarithm of the number two. The telemetry device may determine a second number using one or more bits of the mantissa as an index into a predetermined lookup table. Values of the lookup table may be proportional to logarithms of candidate mantissa values. The telemetry device may determine the compressed number based on rounding of a sum. The sum may include the first and second numbers. The rounding may be based on a predetermined step size.