Adaptive Audio Band Gain for Noisy Telecommunications Terminals
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Solution Overview
Problem
Users of telecommunications terminals face difficulty in hearing audio messages in noisy environments due to insufficient consideration of ambient noise levels in existing signal enhancement methods.
Innovation Solution
A telecommunications terminal with an adaptive enhancement filter that adjusts the gain in specific audio frequency bands based on estimated noise levels, using a processor to calculate a gain factor that enhances the signal in noisy environments without distorting the output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the gain of the received signal is enhanced to improve hearing in noisy environments, then the signal-to-noise ratio improves, but the received signal becomes significantly distorted when gain exceeds a particular level
Solution Approach 1:
The patent divides the audio frequency spectrum into multiple frequency bands and applies different gain values to each band. This segmentation allows selective enhancement of frequencies where noise is most problematic while preserving signal integrity in other bands, resolving the contradiction between improving signal-to-noise ratio and avoiding distortion.
Solution Approach 2:
The patent applies different gain characteristics to different frequency bands based on local noise conditions. By analyzing noise levels in each frequency band separately and applying targeted gain enhancement only where needed, the system improves overall intelligibility without causing distortion in frequencies where the signal is already clear.
2Measurement precision
If spectrum analysis is performed to enhance low signal-to-noise ratio components, then audio intelligibility improves, but the system does not account for ambient noise levels at the receiving terminal
Solution Approach 1:
The patent implements a feedback mechanism where the ambient noise level at the receiving terminal is continuously measured and used to adjust the gain applied to the received signal. The processor analyzes both the received signal spectrum and the locally measured ambient noise, then adapts the frequency-dependent gain to compensate for the specific noise conditions at the user's location, making the system adaptable to different environments.
3Reliability
If adaptive methods are used to enhance signal gain based on noise levels, then hearing ability in noisy environments improves, but the system complexity increases
Solution Approach 1:
The patent uses segmentation of the frequency spectrum into discrete bands, which simplifies the adaptive processing by allowing independent analysis and gain control for each band. This approach reduces computational complexity compared to analyzing the entire spectrum as a single channel, while still providing adaptive enhancement tailored to noise conditions in each frequency region.
Data Source
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AI summary
A telecommunications terminal (100) includes an input audio transducer (111), a receiver (101) for receiving an electrical signal representing a transmitted audio signal, a noise energy estimator (117) for estimating an audio noise energy input received by the input audio transducer and an audio enhancement means (108) for applying to the received electrical signal in a selected audio frequency band a gain which is greater than the gain applied to audio frequencies of the received electrical signal outside the selected band, the gain applied being a function of the audio noise energy input.