Audio Filter Frequency Response Control Under Latency Constraints
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Solution Overview
Problem
Existing filter technologies struggle to accommodate a predetermined latency value without compromising the difference between the target amplitude and phase characteristics of a frequency response, leading to significant discrepancies in the amplitude characteristic of the frequency response.
Innovation Solution
A control method and system that acquire target amplitude and phase characteristics, modify the frequency response to satisfy a specified latency value, and correct the resulting frequency response to minimize the difference between the amplitude characteristic and the target amplitude characteristic, using a processor-based system to adjust coefficients and prioritize corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a filter with finite length is used to accommodate target amplitude and phase characteristics, then the filter can be implemented with practical constraints, but a large difference occurs between the amplitude characteristic of the frequency response and the target amplitude characteristic
Solution Approach 1:
The patent applies preliminary action by first determining the impulse response based on both target amplitude and phase characteristics, then pre-calculating the necessary time-shifting amount before generating the final frequency response. This preliminary determination of the time shift based on latency requirements allows the system to proactively compensate for the finite filter length constraints, thereby reducing the amplitude characteristic difference while maintaining practical implementability.
2Loss of time
If the frequency response is modified to satisfy a predetermined latency value, then the latency requirement is met, but the difference between the amplitude characteristic and target amplitude characteristic increases
Solution Approach 1:
The patent employs parameter changes by dynamically adjusting the time-shifting parameter based on the latency value while simultaneously modifying the frequency response parameters. The system calculates the impulse response with both amplitude and phase characteristics, then applies a specific time shift parameter derived from the latency requirement. This coordinated parameter adjustment allows the system to meet latency specifications while minimizing the impact on amplitude characteristic accuracy through the corrective frequency response generation.
Data Source
AI summary
In a control method of controlling a frequency response of a filter for processing an audio signal, the frequency response is defined by an amplitude characteristic and a phase characteristic. The control method includes: acquiring a target amplitude characteristic, a target phase characteristic, and a latency value; obtaining a first frequency response in accordance with the target amplitude characteristic and the target phase characteristic; obtaining a second frequency response by modifying the first frequency response so that a latency of the second frequency response satisfies the latency value; and obtaining a third frequency response to be set for the filter by correcting the second frequency response, the second frequency response being corrected so as to reduce a difference between (i) an amplitude characteristic of the second frequency response and (ii) the target amplitude characteristic.