+hezkz17 enters digital audio Q&A
Introduction of Shanghai Shanjing DSP Audio Processor:

Shanghai Shanjing DSP audio processor is a digital signal processor, which is specially used for audio signal processing and enhancement. It adopts advanced digital signal processing technology and algorithm, can process audio signals in real time, and has the characteristics of high efficiency, stability and reliability.
The processor can be applied to various audio devices, such as speakers, headphones, audio systems, etc. Through its powerful audio processing capabilities, it can perform noise reduction, reverberation, equalization, compression, limiting, and sound image positioning on audio signals. A variety of processing, so as to achieve the effect of improving sound quality and enhancing sound effect.
In addition, Shanghai Mountain View DSP audio processor also supports a variety of interfaces, including I2S, PCM, SPDIF, etc., which can realize compatibility with various audio chips. At the same time, it also has a flexible configuration function, users can set and adjust parameters according to actual needs, so as to get the best audio effect.
In short, Shanghai Mountain View DSP audio processor is a powerful and stable audio processor, which can help users achieve high-quality sound effects.
The code implements an IIR low-pass filter using three first-order Butterworth filters in series. The initialization function init_lpf() is used to calculate the filter coefficients, and the filter function lpf() receives the input signal xin and calculates the output signal yout.
In the code, N represents the order of the filter, Fc represents the cutoff frequency, Q is the quality factor, x and y are the input and output buffers, respectively, and b and a are the filter coefficients. In the filtering process, the input data x is first shifted up by one bit, and the new output yout is calculated, and then the output data y is shifted up by one bit for the next calculation. Finally return yout as the output result.
It should be noted that other settings and adjustments may be required in practical applications, such as increasing the order of the filter, modifying the cutoff frequency, etc., in order to achieve the desired filtering effect
#include "arc.h"