Floating-Point Signal Compression With 4-Bit Exponent Mapping
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Solution Overview
Problem
Existing data compression methods in digital optical repeaters face challenges in minimizing data loss when compressing signals, particularly due to insufficient bits in the exponent portion of the floating point format, leading to distortion and incorrect data transmission.
Innovation Solution
A data compression device and method that generates a 28-bit fixed-point digital signal by alternately arranging in-phase and quadrature components, then converts it into a 20-bit floating-point signal using a compressor, which includes generating a 4-bit exponent bit string and a 14-bit mantissa bit string, reducing data loss by optimizing bit allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of bits in the exponent portion is increased to minimize data loss, then data accuracy is improved, but the number of bits available for the mantissa portion is reduced, worsening compression efficiency
Solution Approach 1:
The patent changes the parameter of exponent bit allocation from the conventional 3 bits to 4 bits in the floating-point format. This parameter change allows for 16 different exponent values instead of 8, providing sufficient dynamic range to represent various input signal sizes without losing data accuracy, while still maintaining acceptable compression efficiency within the 20-bit constraint
2Productivity
If the number of bits in the mantissa portion is reduced to increase compression efficiency, then compression ratio is improved, but the number of valid bits is reduced, causing incorrect data transmission
Solution Approach 1:
The patent optimizes the mantissa bit allocation to 14 bits within the 20-bit floating-point format. This parameter setting maintains sufficient precision for accurate data representation while achieving effective compression. The balanced allocation ensures that enough valid bits are preserved to transmit correct data without unnecessary waste of compression ratio
3Productivity
If a conventional floating point format with 3-bit exponent is used, then compression efficiency is improved, but the exponent bits are insufficient to represent input size, leading to data distortion
Solution Approach 1:
The patent modifies the exponent portion from 3 bits to 4 bits, changing the representable range from 8 values to 16 values. This parameter change provides adequate coverage for representing different input signal sizes and dynamic ranges, preventing data distortion while maintaining compression efficiency through the optimized 20-bit floating-point structure
Data Source
AI summary
A data compression device includes an analog to digital converter (ADC) configured to convert an analog signal into a digital signal including in-phase and quadrature components; and a compressor configured to generate a 28-bit fixed-point digital signal in which bits of the in-phase and quadrature components are alternately arranged, generate an exponent bit string by comparing n most significant bits of a data bit string excluding two sign bits in the 28-bit fixed-point digital signal with preset mapping data, wherein the exponent bit string includes 4 bits, generate a mantissa bit string composed of 14 bits corresponding to up to 14th bit from a bit next to the n most significant bits of the data bit string, and generate a 20-bit floating point digital signal by combining the two sign bits, the exponent bit string, and the mantissa bit string, wherein n is a natural number equal to or greater than 2 and equal to or less than 12.