Softbit Speech Decoder Loss Concealment Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Softbit speech decoders cease operation when receiving control signals instead of speech data, failing to reduce subjective bit error effects in noisy channels.
Innovation Solution
Incorporation of a speech loss concealment circuit that generates speech-parameter error probability vectors based on a speech information flag, allowing the decoder to continue operating even when no speech data is received, using methods such as previous value, multiple value, or constant vector calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the softbit speech decoder operates normally when receiving speech data, then speech decoding quality is maintained, but the decoder ceases operation when receiving control signals instead of speech data
Solution Approach 1:
The speech loss concealment circuit is designed to handle multiple types of input signals universally. It can process both speech data and control signals by examining the speech information flag and appropriately generating speech-parameter error probability vectors for both cases, making the decoder adaptable to different signal types without ceasing operation
Solution Approach 2:
The system changes its operational parameters based on the input signal type. When control signals are detected (speech information flag indicates no speech data), the parameter generating circuit switches to generating a second speech-parameter error probability vector with different characteristics compared to the first vector generated for speech data, allowing the decoder to adapt its processing to the current signal type
2Reliability
If the parameter transition probability circuit processes speech data to produce error probability data, then bit error reduction is achieved, but no error probability data can be produced when control signals are received
Solution Approach 1:
The speech loss concealment circuit acts as an intermediary between the equivalent channel and the parameter transition probability circuit. It intercepts the speech information flag, determines whether speech data is present, and generates appropriate speech-parameter error probability vectors even when control signals are received, thereby maintaining the error probability data generation function that would otherwise cease
Solution Approach 2:
The system performs preliminary analysis of the speech information flag before processing the main signal. By detecting in advance whether the received signal contains speech data or control signals, the speech loss concealment circuit can prepare and generate the appropriate type of speech-parameter error probability vector in advance, ensuring continuous operation and error reduction capability
Data Source
AI summary
A softbit speech decoder includes a speech loss concealment circuit receiving bit information, bit error probability data, and a speech information flag from an equivalent channel based on a received signal provided to the equivalent channel. The speech loss concealment circuit also contains a speech data judging circuit for judging whether the speech information flag indicates that the received signal contains speech data, a parameter generating circuit for generating output information, including a speech-parameter error probability vector when the speech information flag indicates that the received signal does not contain speech data. When the received signal does not contain speech data, the speech-parameter error probability vector generated by the parameter generating circuit allows the softbit speech decoder to continue operating.