Smart Mixer Latency Reduction via Dual Window Time-Frequency Conversion

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Solution Overview

Problem

Smart mixers experience latency exceeding 20 ms during signal processing, which is undesirable for real-time applications like concert venues and recording studios, where latency should be 5 ms or less to prevent uncomfortable feelings and ensure smooth sound mixing.

Innovation Solution

The implementation of separate time-frequency converters with different window functions for signal analysis and modification, allowing for high-resolution frequency analysis while reducing latency by using a modifying window function with a smaller width than the analyzing window function, and applying the analysis result to the signal modification process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a wide window function is used for frequency analysis, then frequency resolution is improved, but latency increases

Engineering Contradiction:

Improvefrequency resolutionVSAvoidlatency

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent divides the signal processing into two separate paths: one using a wide window function for high-resolution frequency analysis, and another using a narrow window function for low-latency signal modification. This segmentation allows each path to be optimized for its specific function without compromise.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary component that generates modification values based on the frequency analysis results from the wide window path, then applies these modifications through the narrow window path. This intermediary mechanism transfers information between the two paths without requiring them to use the same window function.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If sufficient frequency analysis is performed, then analysis accuracy is improved, but processing time increases

Engineering Contradiction:

Improveanalysis accuracyVSAvoidprocessing speed

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent segments the processing into an analysis phase using a wide window function for high accuracy, and a modification phase using a narrow window function for fast processing. This allows accurate analysis without sacrificing overall processing speed.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs the computationally intensive frequency analysis using the wide window function in advance, then uses the resulting modification values to guide the faster narrow window processing. This preliminary action allows the system to prepare accurate analysis results before real-time modification is needed.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11516581B2Information processing device, mixing device using the same, and latency reduction method

Publication Date: 2022.11.29 HIBINO

AI summary

An information processing device includes a first time-frequency converter configured to perform a time-frequency conversion with respect to an input signal, using a window function having a first width, a second time-frequency converter configured to perform a time-frequency conversion with respect to the input signal, using a second window function having a second width smaller than the first width, and a modification processing unit configured to modify an output of the second time-frequency converter, using a frequency analysis result based on an output of the first time-frequency converter.