signal-processing

问题 First, please excuse my ignorance in this field, I'm a programmer by trade but have been stuck in a situation a little beyond my expertise (in math and signals processing). I have a Matlab script that I need to port to a C++ program (without compiling the matlab code into a DLL). It uses the hilbert() function with one argument. I'm trying to find a way to implement the same thing in C++ (i.e. have a function that also takes only one argument, and returns the same values). I have read up on

问题 I am implementing MFCC algorithm with Java. There is a sample code for triangular filters and MFCC at Java. Here is the link: MFCC Java However I should follow that code written in Matlab: MFCC Matlab My question is that at Matlab code it talks about linear and logarithmic filters however there is nothing about that at Java code . I should measure the performance of logarithmic and linear filters but I implemented that Java code and there is nothing about that. Also I didn't understand what

问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: Real time pitch detection Determine the audio frequency of sound received via the microphone I'm developing my own android guitar tuner. Here I will have to use the guitar note frequency. Therefore, I want to know how to convert the sound coming through the mic port into its frequency in android? 回答1: EDIT: link dead ---This problem is already solved here--- I shall summarize the paper : Record stuff : int

问题 I am implementing BFSK frequency hopping communication system on a DSP processor. It was suggested by some of the forum members to use Goertzel algorithm for the demodulation of frequency hopping at specific frequencies. I have tried implementing the goertzel algorithm in C. the code is follows: float goertzel(int numSamples,int TARGET_FREQUENCY,int SAMPLING_RATE, float* data) { int k,i; float floatnumSamples; float omega,sine,cosine,coeff,q0,q1,q2,result,real,imag; floatnumSamples = (float)

问题 I'm having difficulty implementing an FFT using vDSP. I understand the theory but am looking for a specific code example please. I have data from a wav file as below: Question 1. How do I put the audio data into the FFT? Question 2. How do I get the output data out of the FFT? Question 3. The ultimate goal is to check for low frequency sounds. How would I do this? -(OSStatus)open:(CFURLRef)inputURL{ OSStatus result = -1; result = AudioFileOpenURL (inputURL, kAudioFileReadPermission, 0,

问题 TL;DR : Is there a C++ implementation of RANSAC or other robust correspondence algorithms that is freely usable with arbitrary 2D point sets? I know that many implementations exist that include or make use of correspondence algorithms such as RANSAC (Random Sampling Consensus). They are often used in computer vision applications and found in libraries such as OpenCV, PCL, etc. The general algorithm is well known and various site lists the different steps. Now, all the "advanced"

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 12 months ago . I'm designing a simple tuner, so my target is displaying a note name (A, B, F#) and the distance in cents between the theoretic sound and the actual input. I'm completely new to audio and signal processing, so I did some research and I found a thing called Fast Fourier Transform that will analyze the bytes and

问题 does anyone know how to make a simple EQ audio unit (3 bands - low, mid, hi) with iOS ? I know how to add an iPod EQ Audio Unit to my AU Graph. But it only give you access to presets and I need proper control of the EQ. I've looked around for some tutorials or explanations but no luck. Thanks. André 回答1: The iPhone doesn't exactly support custom AudioUnits. Or, more precisely, it doesn't allow you to register an AudioUnit's identifier so you could load it in an AUGraph. You can, however,

问题 does anyone know how to make a simple EQ audio unit (3 bands - low, mid, hi) with iOS ? I know how to add an iPod EQ Audio Unit to my AU Graph. But it only give you access to presets and I need proper control of the EQ. I've looked around for some tutorials or explanations but no luck. Thanks. André 回答1: The iPhone doesn't exactly support custom AudioUnits. Or, more precisely, it doesn't allow you to register an AudioUnit's identifier so you could load it in an AUGraph. You can, however,

问题 I need to generate a tone that I can manipulate frequency and wave. The overall goal is to create a basic piano. Does anyone know how I can achieve this? My development platform is the iPhone 2.x 回答1: You could always start with sin waves. :-) #include <cmath> typedef double Sample; typedef double Time; class MonoNote { protected: Time start, duration; virtual void internalRender(double now, Sample *mono) = 0; public: MonoNote(Time s, Time d) : start(s), duration(d) {} virtual ~MonoNote() {}