Questions tagged [wave]

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19 views

How can I Improve my 2D Fourier Transform Graph?

I'm very new to signal processing. I have been tasked with running Fourier analysis on some velocity waves that I have found in a simulation. My supervisor would like me to plot the angular velocity ...
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26 views

Efficient Method for Interpolating between bins in FFTW

I'm working on some oscillator classes right now and perform FFT around 100 times per second. The issue I'm running into is interpolating between the bins so there is not a noticeable change from each ...
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1answer
40 views

Playing sounds with only one frequency at a time

We have a "speaker", that can make a single frequency at a time (0 - 130k Hz). So we can play a tune by making it play a tone for 1 sec and then the next tone for 0.5 sec etc. We can change ...
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58 views

Wave Digital Filter Diode Equation?

I'm trying to understand how diode circuits are implemented in wave digital filters, particularly for clippers. The research papers and other sources I've looked at use the equation $$I(V) = 2I_s \...
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34 views

Possibilities in Audio Convolution Math

New Python user here! I am a musician working on a program to streamline a process of using convolution math on a folder of .wav samples. The idea is that each audio sample will be multiplied with ...
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21 views

Identifying sounds patterns from wav file

I have an audio recording stored as a .wav file. My goal is to identify exact sounds patters from it using Python. The problem I'm facing is there's a clear "ting" sound in the audio file, ...
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32 views

Generating a sawtooth function with a variable frequency

So I'm trying to write a script that produces a sawtooth function using the equation: s = 2 a / π atan ( cot ( π f t ) ) Where: a : amplitude f : frequency t : time It's all working fine when f is ...
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2answers
256 views

DFT of pure sinusoidal wave

I'm writing a program in which you can synthesize waves by adding to a sound's Fourier transform, and then inverse the transform to get the modified sound. In order to do this, I need to know what to ...
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0answers
30 views

Is it possible to open 2 streams from the same microphone on Oboe?

I'm trying to open 2 input streams from the same microphone on Oboe but it's not working. One of the audio inputs I'm opening is like this: ...
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2answers
192 views

How to merge 2 WAV files together? Can I take the average of the 2 audio file float values? [duplicate]

I'm trying to do one simple thing on Google's C++ Oboe library: pick 2 recordings and merge both. That is, make as if the 2 were playing at the same time. Oboe works with Float numbers from -1.0 to +1....
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4answers
583 views

Reconstructing a sine wave from an interval shorter than half its wavelength

I know that the function that I search is a sine wave of the form $$A \cdot \sin(x) $$ where my $A$ is unknown. I have samples of the sine wave at discrete points within an interval that's shorter ...
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0answers
35 views

Hello World Example of a Digital Waveguide in JavaScript

I am just learning about sound so might be jumping the gun a bit. But it helps me stay motivated and get into an interesting problem to solve to ask these more complicated questions. I am looking at ...
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2answers
65 views

What do troughs represent in a sound wave?

What's the notion of negative amplitude? I hope the title and the question don't mean different things.
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1answer
141 views

What is the actual format of this audio file?

I am collecting some data from jotform .wav widget. All the audio files are in .wav format. But when I tried to open the file using python ...
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3answers
49 views

How does voice affect a sound wave or its corresponding waveform?

Someone in the physics stack exchange told me to come here for this question. My question is how does a person's voice affect how a soundwave looks? For example, if I say the letter "a" it ...
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1answer
84 views

Does Radio Communication Have to Account for the Doppler Effect?

I know that radio communications take place in specific frequency bands, and that the doppler effect can cause shifts in frequency when there is relative motion between the source and destination ...
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1answer
48 views

harmonic waves as integer multiple in spectrum

i have a motor that is rotating with a certain frequency. If i check the frequency spectrum it contains a peak on 150 hz. Also i have peaks at 300,450,600 ... i guess that those peaks are harmonics. ...
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1answer
183 views
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2answers
149 views

Types of interpolation used for reconstruction in DSP?

What are the different types of interpolation used in DSP for reconstruction of analog signal from discrete/digital signal I am able to somehow learn two types of interpolation 1st is "zero order ...
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1answer
63 views

How to Save FFT output for fast read-in?

For a project, I'm reading in hundreds of short (4 sec) wavefiles and giving them to scipy fft for the frequency information for further processing/experimenting in various ways. Problem is, I want to ...
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0answers
18 views

Digital signal processing how audio wave and function chage with respect to each other

If an audio signal is f(t) and if i play same audio with 2× speed then what will function of 2× speed signal f(2t) or f(t/2) and why?
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1answer
58 views

Mix N sinusoidal waveforms without clipping but at a costant amplitude with no clipping and maximum amplitude

I need to mix "n" sinusoidal waveforms which can be all active or some or all can be silent. The math seemed simple (working with float32 samples) because I just added all waveforms and then divide ...
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0answers
72 views

Clip wav by PSD

I have the following two things. sequence_1: Sound file in the wave format. PSD_1: Some PSD (Power Spectral Density). I want that the PSD(sequence_1) < PSD_1 for all indices. How I think about ...
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1answer
92 views

Where should triangle, sawtooth and square waves start?

I am reading a text on DSP, which shows generation of sin, cos, triangle, sawtooth and square waves. Generated cos waves start at 1 and sin waves start at 0, which makes sense (cos(0)=1, sin(0)=0). ...
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48 views

Need help with detecting onset of audio in wav file

I'm new to DSP and I'm learning as I go. I have an audio file with a chirp signal(2kHz). I played and recorded this chirp signal and the recording has a lot of environmental sounds. Here is my code:
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2answers
225 views

Why do waveforms that are symmetrical above and below their horizontal centerlines contain no even-numbered harmonics?

All About Circuits site states that waveforms that are symmetrical above and below their horizontal centerlines contain no even-numbered harmonics. Can somebody explain this mathematically, or point ...
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1answer
50 views

are Ultra sound signal amplitude dangerous? [closed]

First sorry if this question if it's out of topic but I'm very intrigued The human ear can hear a specific range of sound waves frequency. and huge amplitude of those sounds can damage the ears but ...
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2answers
82 views

difficulty in understanding amplitude, frequency and period

I have difficulty in understanding of some fundamental terms as amplitude. Can be there more than one amplitude for a signal? The following expression is combination of 3 sinusoidal signal, so are ...
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1answer
159 views

Is it possible to encrypt an audio wave? NFL Example

In the NFL, quarterbacks receive playcalls from coaches over their helmet's wireless interface. Someone mentioned how occasionally, these radios will pick up interference from airplanes, and that ...
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1answer
81 views

frequencies in sound: multiple possibilities?

First, I am by no mean a sound engineer (as you will guess later). I was just wondering something while looking at the waveform of a .wav for a given shape of waveform on a duration of 2 sec for ...
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1answer
3k views

Extracting metadata from wav files [closed]

I was curious if there is a way to extract metadata from wav files. For instance, can you get bpm, key, instrument, etc. from a .wav file on upload?
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2answers
101 views

How to Extract a Period of a Periodic Pulsed Signal?

I rercorded a sequence of zeros and ones which is repeated many times. However, the first and the last repetitions may not be complete because I have to start recording at a random time, so the ...
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1answer
232 views

Windows Audio WAVEFORMAT buffer BYTE to 16-bit int

I am trying to understand audio-buffer processing at the low-level for the first time. I have the following C++ code copying WAVE-format byte data from capture buffer of Window Core Audio (*ppData in ...
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1answer
275 views

How to compare two audio files that maybe have been recorded in the same environment

I have two audio files that I think they were recorded in the same room. Is there any tool that can be used to compare both of them. Knowing that sample rate and format are the same. Thanks
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0answers
245 views

Equation for impulse train

I am looking for a formula (Fourier series) to generate an impulse train waveform - a spike-wave with amplitude and period both $1$ – so that $f(x)$ has value $1$ at $x = 1,2,3,4...$ and $f(x)$ has ...
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2answers
7k views

Mathematical equation for the sound wave that a piano makes

Is there a mathematical function that can output the sound that a piano makes at different frequencies? So if the simplest equation for a sound wave (at a given frequency and for a given sample rate) ...
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2answers
80 views

Pitch fluctuates unexpectedly in simple sine function

I wrote a very basic C program to play a sine of a user-specified frequency. In the interest of portability, I have it spit values directly to stdout, so hopefully you can reproduce my problem on your ...
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1answer
160 views

When simulating a voltage divider using wave digital filters I get inversed polarity outputs

I'm studying wave digital filters for my bachelor's thesis and I'm finding problems in implementing a voltage divider to test my knowledge. Here's the circuit that I'm trying to simulate and the WDF ...
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1answer
243 views

wavwrite with 32 bits per sample seems to overflow?

I am trying to generate a 32bit PCM wav file with octave, the file shall contain a single full-scale sample (0db impulse). I am getting the expected result when using 24 bits per sample: ...
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1answer
60 views

Is there a special case in which wave atoms convert to curvelets?

I'm new to multi scale transformations. I was wondering if there is a special case where wave atom converts to curvelet transform? Can I use wave atom parameters to have curvelet properties?
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1answer
327 views

How to triangulate 2 sources on a 2d plane formed by 4 sensors?

I have 4 sensors capturing signal data. Signal distribution speed is constant and known. I have sensors positions in 3d space. Also, I have an amplitude/frequency decomposition for data received by ...
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1answer
2k views

How to “draw” the function/wave to send symbols using QAM?

Say you have the following 8QAM constellation diagram: Say, you want to send the sequence: 001 110 101 000 001 How would you draw the function/wave containing the symbols? My problem in ...
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1answer
45 views

In DSP - is it true that the only type of interfering wave occurs when frequencies match? [closed]

Therefore, any other frequency, no matter the amplitude, won't interfere or degrade original wave in the DSP frequency domain systems?
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1answer
374 views

Pulse wave from sum of sinusoids

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1answer
1k views

Combining 2 sinusoids of equal amplitude with different frequencies into 1 new “wave”

This question is about combining 2 sinusoids with frequencies $\omega_1$ and $\omega_2$ into 1 "wave shape", where the frequency linearly changes from $\omega_1$ to $\omega_2$, and where the wave ...
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1answer
571 views

How do I sum the discrete cosine transform cosine waves?

Sorry if this sounds like a stupid question, I'm new to DCT. I've implemented various types of DCT (like IV and II) and they all give vastly different coefficients. From what I've read, the DCT ...
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1answer
719 views

How audio watermarks are captured

I have read that we can use audio watermarks to "identify the original produces of the material or the consumers of the media." How consumers of the media is measured by audio watermarks? Lets say ...
2
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1answer
341 views

Why LFO should be alias-free?

I'm really tripping about this point! I try to reason with you and explain what's my trouble. Consider a scenario with Sample Rate 44100hz and a LFO square wave that will modulate some internal ...
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1answer
1k views

Generate loopable sine wave cycle for given frequencies

I am somewhat new to DSP so bare with me. I am working on a simple wavetable oscillator. What I am trying to do is generate one cycle of a wave form for each note (frequency) and store it in an array ...
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2answers
218 views

How to mix two audio files recorded with different settings to obtain a realistic result

I am a software engineer, currently working on a signal-processing related project, which I am new to. For evaluating the algorithm(which is written in R), I need to mix (merge) two different audio ...