Loudspeaker Testing via Digital Pulse Duty Cycle Variation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for checking loudspeaker arrangements in vehicles lack sufficient testing depth and reliability, particularly in ensuring functionality and detecting short-circuits, often requiring complex components like microphones.
Innovation Solution
A method and device that supply a loudspeaker with a digital pulse test signal with a changing duty cycle, allowing for a continuity and short-circuit check, and classify the loudspeaker as functional based on voltage drop measurements across a reference circuit, without needing complex components like microphones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a digital pulse test signal with changing duty cycle is used, then testing depth and reliability are improved, but device complexity increases
Solution Approach 1:
The patent applies periodic action by using a pulse test signal with varying duty cycles to systematically test different operational states of the loudspeaker. The duty cycle changes periodically from 0% to 100% in multiple stages, allowing comprehensive functionality verification through repeated cyclic testing patterns that cover various operating conditions.
Solution Approach 2:
The patent implements dynamics by dynamically adjusting the duty cycle of the test signal during the testing process. The duty cycle is not static but changes over time according to a predetermined pattern, enabling the test system to adaptively probe different operational modes of the loudspeaker and drive circuit without requiring multiple separate test equipment.
2Reliability
If a digital pulse test signal with changing duty cycle is used, then testing depth and reliability are improved, but cost increases
Solution Approach 1:
The patent applies self-service by designing a test system that uses the loudspeaker's own drive circuit and existing components to perform the testing. The system leverages the existing reference circuit and voltage drop measurement capabilities already present in the loudspeaker assembly, eliminating the need for external expensive test equipment and reducing manufacturing costs while maintaining high testing reliability.
3Measurement precision
If the pulse frequency is greater than the natural frequency of the loudspeaker membrane, then natural oscillation is avoided, but the testing becomes more complex
Solution Approach 1:
The patent applies parameter changes by carefully selecting and controlling the pulse frequency parameter to be greater than the natural frequency of the loudspeaker membrane. This parameter adjustment prevents resonance and natural oscillation during testing, ensuring that voltage drop measurements accurately reflect the electrical characteristics rather than being contaminated by mechanical vibrations, thereby improving measurement precision.
4Object-affected harmful factors
If the duty cycle increases and decreases over several periods, then the loudspeaker membrane deflection is controlled to be inaudible, but the test sequence duration increases
Solution Approach 1:
The patent applies periodic action by structuring the duty cycle changes to occur over multiple periods of the test sequence duration. The duty cycle increases from 0% to 100% and decreases back to 0% in a controlled periodic manner, ensuring that the loudspeaker membrane deflection remains below audible thresholds while completing comprehensive functionality tests within an acceptable time frame.
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
Enables a high-level, cost-effective, and reliable check of loudspeaker arrangements with increased testing depth and reliability, avoiding audible sound waves and minimizing storage requirements.
Implementation Method 1
The loudspeaker has a loudspeaker membrane for generating an acoustic signal... the loudspeaker is supplied with a digital pulse test signal
Implementation Method 2
a measured variable is recorded which is representative of a voltage drop across a reference circuit connected in series with the loudspeaker
Data Source
Figure 1
Figure 2~4
AI summary
The loudspeaker arrangement (10) comprises a loudspeaker (20) and a trigger circuit (30) for electrically triggering the loudspeaker (20). The loudspeaker (20) has a loudspeaker diaphragm for generating an acoustic signal. A digital pulse test signal (P) is applied to the loudspeaker (20) via the trigger circuit (30) during a respective test sequence (TS), the digital pulse test signal having a duty cycle that is predetermined to change in such a manner that the duty cycle increases over a plurality of periods of the test sequence (TS) at the beginning of the test sequence (TS), and the duty cycle decreases over a plurality of periods of the test sequence (TS) at the end of the test sequence (TS). During the respective test sequence (TS), a measurement variable (U), which is representative of a voltage drop on a reference circuit (39) connected in series to the loudspeaker (20), is detected, and the loudspeaker arrangement (10) is classified as functional on the basis of a comparison of the measurement variable (U) and a predetermined reference value.