FSK Voice Communication Quality Judging via Redundant Bits
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Solution Overview
Problem
Existing communication systems face challenges in accurately and efficiently judging communication quality, especially at low bit rates, due to complex device constructions and potential errors in real-time voice transmission, particularly when noise is present.
Innovation Solution
A communication quality judging device and method that identifies redundant bits in a baseband signal to assess channel quality, allowing for rapid judgment and adaptive data processing, such as attenuating or replacing data, to maintain sound quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cycle redundancy check (CRC) codes are added to ensure sufficient sound quality at low bit rate, then communication reliability is improved, but device complexity and processing load increase making real-time transmission difficult
Solution Approach 1:
The patent extracts only the essential error detection function from complex CRC codes, using simple parity bits instead. This reduces the redundancy overhead and processing complexity while maintaining sufficient error detection capability for low bit rate voice transmission.
Solution Approach 2:
The patent changes the error detection parameter from multi-bit CRC codes to single-bit parity checks. This parameter simplification reduces computational complexity and enables real-time processing while maintaining adequate reliability for the application.
2Measurement precision
If fine level sampling and complex calculation are used to measure instantaneous value difference at Nyquist point, then measurement precision is improved, but device complexity increases making real-time transmission difficult
Solution Approach 1:
The patent uses simple, computationally inexpensive quality assessment metrics that can be calculated rapidly with minimal processing power. Instead of precise instantaneous value measurements, it employs simpler indicators that provide sufficient quality assessment for real-time decision making.
Solution Approach 2:
The patent applies partial action by using simplified measurement approaches that do not require full precision. The quality assessment uses sufficient but not excessive measurement detail, enabling real-time processing while achieving adequate accuracy for the application.
3Reliability
If forward error correction (FEC) is applied to correct errors, then communication reliability is improved, but device complexity increases and real-time transmission becomes difficult
Solution Approach 1:
The patent extracts only the essential error detection capability from complex FEC schemes, using simple parity bit checks instead. This reduction maintains sufficient error detection for voice transmission while eliminating the excessive processing complexity of full FEC implementation.
4Ease of operation
If electric field strength measurement is used to judge communication quality, then ease of operation is improved, but measurement precision deteriorates when voice data is mixed with noises
Solution Approach 1:
The patent introduces an intermediary quality assessment mechanism that processes the received signal through simple evaluation criteria. Instead of directly measuring electric field strength, it uses intermediate quality indicators that are less susceptible to noise interference while maintaining ease of implementation.
Data Source
AI summary
A device and method for effectively judging a communication quality in a communication system and a program used for the judgment. A communication device generates a four-value FSK symbol by adding a redundant bit to a bit of the most important part of encoded audio data. The symbol containing the redundant bit is set so that the symbol value is the maximum value of the minimum value of the four values which may be obtained. A reception device R receives the FSK modulation wave, restores the symbol, counts the number of redundant bits contained in the restored symbol and having incorrect values, decides whether to perform a bad frame masking process and what kind of bad frame masking process is to be performed, and executes the decided process. Thus, it is possible to accurately or rapidly judge the communication quality with a simple configuration.