Noise Measurement Using FFT and Parseval's Theorem
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Solution Overview
Problem
The existing methods for measuring total sound pressure level of noise, such as the octave accumulation method, require extensive filtering and calculation, leading to slow measurement speeds.
Innovation Solution
A method that directly obtains a time domain digital signal of sound pressure noise, converts it to a frequency domain signal using FFT, calculates the sound pressure effective value based on Parseval's theorem, and then converts this value to the total sound pressure level without filtering, simplifying calculations and increasing measurement speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the octave accumulation method is used to measure total sound pressure level, then measurement accuracy is maintained, but measurement speed decreases due to extensive filtering and calculation
Solution Approach 1:
The patent extracts and eliminates the filtering step from the traditional octave accumulation method. By directly calculating the total sound pressure level from the original noise signal without requiring octave band filtering, the invention removes the computational bottleneck while maintaining measurement accuracy through direct energy summation in the frequency domain
Solution Approach 2:
The patent replaces the mechanical filtering process with a direct mathematical calculation approach. Instead of using physical or digital filters to decompose the signal into octave bands before accumulation, the invention uses a direct calculation formula that computes total sound pressure level from the original signal's frequency components, substituting a complex mechanical process with a simpler computational method
2Measurement precision
If extensive filtering is performed before accumulation in the octave method, then frequency analysis accuracy is improved, but calculation complexity increases
Solution Approach 1:
The patent extracts the essential measurement goal (total sound pressure level) from the complex filtering process. By taking out the filtering step entirely and directly calculating the desired parameter from the original signal, the invention reduces calculation complexity while maintaining the ability to obtain accurate frequency domain information through direct transformation
Solution Approach 2:
Instead of following the traditional approach of filtering first then accumulating, the patent inverts the process by directly calculating the total sound pressure level from the original signal's frequency components. This inversion eliminates the intermediate filtering step and its associated computational complexity
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 allows for faster and more efficient measurement of total sound pressure level by eliminating the need for filtering, resulting in quicker and more straightforward calculations.
Implementation Method 1
a frequency domain signal of the sound pressure signal is obtained according to the time domain digital signal
Implementation Method 2
a sound pressure effective value of the sound pressure signal is obtained based on the frequency domain signal and according to Parseval's theorem
Data Source
AI summary
A method and a system for measuring a total sound pressure level of noise, and a computer readable storage medium are provided. The method includes: obtaining a time domain digital signal of a sound pressure signal of the noise; obtaining a frequency domain signal of the sound pressure signal according to the time domain digital signal of the sound pressure signal; obtaining a sound pressure effective value of the sound pressure signal based on the frequency domain signal and according to Parseval's theorem; and converting the sound pressure effective value into the total sound pressure level of the noise.