Building Intercom Audio Detection Using ITU-T P.50 Voice Signals

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Solution Overview

Problem

Existing methods for detecting acoustic transmission characteristics in building intercom systems are inaccurate due to the use of inappropriate sound sources and neglect of real-world installation environments, which leads to incorrect assessment of equipment performance, especially for systems with noise suppression and echo cancellation features.

Innovation Solution

A detection system that uses specific voice signals, such as P.50 or P.501 simulation voice signals from ITU-T, and measures sound pressure to calculate acoustic characteristic parameters, including loudness rating, frequency response, distortion, and sidetone masking rating, while simulating real-world environments by adjusting the installation positions of telephones to account for reflection effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If single sounds or frequency sweep sounds are used as test sound sources, then the detection process is simple, but the detection accuracy deteriorates because these sounds are inhibited by noise suppression and echo cancellation functions

Engineering Contradiction:
Improvedetection process simplicityVSAvoiddetection accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent changes the parameter of sound source type from simple single tones or frequency sweeps to complex voice signals with specific spectral characteristics. This parameter change allows the test signals to penetrate through noise suppression and echo cancellation functions while maintaining detectability, thereby resolving the contradiction between operational simplicity and measurement precision.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses voice signals that copy the spectral characteristics of human speech rather than using artificial test tones. This copying approach ensures that the test signals resemble actual voice traffic, making them less susceptible to inhibition by noise suppression algorithms while still providing accurate measurement of acoustic transmission characteristics.

Inventive Principle:
Principle #26Copying

2Productivity

If pink noise or white noise are used as standard sound sources, then the detection can be performed, but the detection accuracy deteriorates because these noises are easily inhibited by noise suppression functions

Engineering Contradiction:
Improvedetection capabilityVSAvoiddetection accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent changes the spectral parameters of the test signal from broad-band noise (pink/white noise) to voice-like signals with specific frequency distributions. This parameter change makes the test signals more resistant to inhibition by noise suppression functions while maintaining their ability to propagate through the acoustic channel for accurate measurement.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the potential harm of noise suppression functions into a benefit by using voice signals that are designed to withstand such processing. The test signals are constructed to have spectral characteristics that allow them to penetrate through noise suppression and echo cancellation, turning what would be a hindrance into a feature that validates the system's performance under real operating conditions.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Device complexity

If detection is performed without simulating real installation environment, then the detection process is simple, but the detection accuracy deteriorates due to neglect of reflection effects

Engineering Contradiction:
Improvedetection setup complexityVSAvoiddetection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the detection system into distinct functional components: sound source generation, acoustic transmission path, and measurement system. By segmenting the setup and using standardized interfaces, the patent achieves accurate measurement of acoustic characteristics while maintaining manageable complexity in the detection process.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary measurement system that captures acoustic signals at standardized positions. This intermediary apparatus allows for accurate measurement of sound pressure and acoustic characteristics while providing a standardized interface that simplifies the overall detection process and ensures reproducibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach significantly improves the accuracy of detecting acoustic transmission characteristics, providing results that better reflect actual usage conditions and equipment quality by considering background noise and environmental reflections.

Implementation Method 1

the sound source portion produces specific voice signals, wherein the specific voice signal includes a P.50 simulation voice signal or a P.501 human voice signal

Methodology Applied
Scientific EffectAcoustic signal generation: Sound

Implementation Method 2

the measuring device measures a sound pressure related to the detected output voice signal based on the detected output voice signal

Methodology Applied
Scientific EffectSound pressure measurement: Sound

Implementation Method 3

transmitting the specific voice signal in the detected pathway, and outputting the specific voice signal as a detected output voice signal

Methodology Applied
Scientific EffectAcoustic signal transmission: Sound

Data Source

PatentEP3057333B1Detection method and detection system for audio transmission characteristic of building intercom system
Publication Date: 2019.07.24 THE THIRD RES INST OF MIN OF PUBLIC SECURITY
  • EP3057333B1 patent drawingFigure 1
  • EP3057333B1 patent drawingFigure 2A~2B
  • EP3057333B1 patent drawingFigure 2C~2D

AI summary

The present application relates to a detection method and a detection system for an audio transmission characteristic of a building intercom system. The method comprises: a sound source portion generating a specific voice signal, and inputting the specific voice signal to a detected channel as an input voice signal, transmitting the specific voice signal in the detected channel and outputting the specific voice signal as a detected output voice signal, wherein the specific voice signal comprises an ITU Telecommunication Standardization Sector (ITU-T) P.50 simulated voice signal or P.501 human voice signal; and based on the detected output voice signal, measuring a sound pressure relevant to the detected output voice signal, and according to the sound pressure which is obtained by measurement and is relevant to the detected output voice signal, calculating an audio characteristic parameter value, so as to determine an audio transmission characteristic of the detected channel. By improving a sound source, a backplane and audio distortion measurement, the solution of the present application improves the detection accuracy of an audio transmission characteristic of a simulated (bus-mode) building intercom system and the accuracy of a detection result, so that the detection is closer to an actual use effect.