Multi-Channel Audio Measurement Using Time-Offset Chirp Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multi-channel audio systems face challenges in simultaneously testing channel characteristics due to crosstalk, which degrades channel quality and makes testing slower and more expensive, especially in production settings, as existing methods require testing each channel separately to avoid crosstalk.
Innovation Solution
A method and apparatus that apply different chirp signals to multiple channels with a predetermined time interval, using a log-swept sine chirp to distinguish harmonic distortion components and separate crosstalk from non-crosstalk components in the output signals, allowing for simultaneous measurement of channel characteristics and crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If each channel is tested separately with other channels grounded to avoid crosstalk, then measurement accuracy is improved, but testing time increases and productivity decreases
Solution Approach 1:
The patent applies periodic action by using time-delayed chirp signals for different channels. Each channel receives a chirp signal at a different time offset, allowing simultaneous testing while distinguishing channel responses through temporal separation. This resolves the contradiction by enabling parallel testing (improving productivity) while maintaining measurement accuracy through time-based channel identification.
Solution Approach 2:
The patent implements preliminary action by pre-calculating and storing impulse responses for different time delays before actual testing. The system pre-processes reference chirp signals and stores their impulse responses in memory, allowing rapid comparison and subtraction during simultaneous multi-channel testing. This preparation enables accurate crosstalk removal without requiring sequential testing.
2Productivity
If simultaneous testing of multiple channels is performed, then productivity is improved, but measurement precision deteriorates due to crosstalk
Solution Approach 1:
The patent extracts crosstalk components from the measured signals by identifying and removing contributions from other channels. The system separates the desired channel response from unwanted crosstalk by using the stored impulse responses of isolated channel measurements, allowing accurate extraction of each channel's true characteristics even during simultaneous testing.
Solution Approach 2:
The patent uses stored impulse responses as intermediaries to facilitate simultaneous measurement. These pre-measured impulse responses act as reference templates that mediate between the simultaneous multi-channel signals and the individual channel characteristics, enabling the system to distinguish and isolate each channel's response from the mixed simultaneous signals.
3Speed
If a linear chirp is used for testing, then testing speed is improved, but the ability to distinguish harmonic distortion from linear characteristics is lost
Solution Approach 1:
The patent changes the frequency-time parameter relationship of the chirp signal from linear to exponential. This parameter change causes harmonic distortion components to appear at different time offsets from the fundamental frequency response, enabling their distinction and separate measurement while maintaining the speed advantages of chirp-based testing.
Data Source
AI summary
A method and apparatus for measuring channel characteristics of a multi-channel system. In accordance with the method and the apparatus, a first chirp is applied as an input to one channel of a multi-channel system at a first time, and a second chirp is applied as an input to another channel of the multi-channel system at a second time, the second time being separated from the first time by a predetermined first time interval. An output signal is acquired from a selected one of the channels. At least one crosstalk component is separated from non-crosstalk components in the output signal to characterize the selected channel based on non-crosstalk components. Preferably, the chirp is an exponential chirp that enables harmonic distortion components to be distinguished and measured in one channel in the presence of crosstalk from one or more other channels.