Audio resampling method

Abstract

The invention discloses an audio resampling method, comprising the following steps: (A) generating finite impulse response filter coefficients and constituting a coefficient table to be stored in an external memory; (B) initializing parameters; (C) pre-treating the input audio sample; and (D) performing interpolation treatment correspondingly in an upward resampling process, and performing extraction treatment correspondingly in a downward resampling process; and outputting the audio sample after resampling. The invention has the advantages that each parameter of a filter is calculated in advance and constitutes a parameter table written in the external memory like a flash memory, thus reducing calculation intensity in algorithm, simplifying code implementation correspondingly, improving calculation efficiency and lowering occupied CPU resource; and only about 10MHz basic frequency is needed even under the ARM7 processor; the processed audio has complete signals, no loss of frequency spectrum and no increased redundant frequency spectrum; and the audio data with different sampling frequencies can be converted into audio data with identical sampling frequency by resampling, thus achieving the sound mixing effect.

Description

technical field [0001] The invention relates to a data resampling method, in particular to an audio frequency resampling method. Background technique [0002] In the field of digital signal processing, the problem of sampling rate conversion is often encountered, such as enlarging or reducing the sampling rate, that is, the problem of resampling. The re-sampling technology is to process one set of digital signals into another set of digital signals, which can be realized by special hardware or by software. At present, the signal acquisition instruments put into use in China all have the resampling function realized by hardware method. The vibration signal is obtained by the sensor, and after low-pass filtering by the filter circuit, the digital extraction is performed by the hardware circuit. This method, which relies on hardware filtering and decimation, is inflexible and expensive. Therefore, software methods are often used to achieve resampling. [0003] The software ...

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Problems solved by technology

[0006] In addition to performing FIR filtering on the input signal above 7th order, the above implementation method also needs to transform the time-domain signal to the frequency domain for processing, and then convert it back to the time-domain output, which requires a relatively large amount of calculation.

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