# Questions tagged [wave]

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158 views

### How to calculate a 3D Fourier Transform?

I am currently employing a centered finite difference method to simulate the excitation of a circular membrane by a forcing term in Python, and the code is functioning as intended. To further enhance ...
82 views

### what am i not doing right while using squarewaves?

I have been applying square waves at 40hz and 10 volts via a function generator amplified by a power amplifier by 2 times(2A) on a 6mm steel specimen. My signals captured from the AE sensor are not ...
93 views

### How to generate square wave from sin and cos?

I have a signal that looks almost like a perfect square wave. When looking at its FFT, I see that the real part has components at the fundamental and third harmonic of almost equal magnitudes. When ...
65 views

### What effect causes this Pattern?

I've conducted a measurement of underwater noise in a laboratory experiment. Therefore i am using a sweep signal. Sometimes -I guess when the signal is much more louder- I get this fascinating ...
100 views

### How to fit a rectangular wave to a signal?

I have some binary data that mostly comes under the form of a rectangular signal. In order to "idealize" my signal I would like to fit a rectangular wave that best represent my signal (Here ...
1 vote
112 views

### How to merge audio better?

I try to use a denoising algorithm to process an audio in streaming mode. What I've done is spliting the audio into 0.5s long segments and use denoising algorithm respectively.Then use np.cat or np....
212 views

### How to calculate the phase difference between two squarewaves of same frequency but different dutycycle?

I have two squarewaves of the same frequency but with different dutycycle. How can I calculate the phase difference between the two? I know that for sinewaves one can use the correlation coefficient, ...
18 views

### sinusoidal waves for texture similarity

I created an algorithm that approximates the tiny image texture by a series of sinusoids. It is NOT Fourier or discrete cosine because the boundary is highly irregular. I have each wave's frequency, ...
440 views

### Resampling to the same sample rate via Python

I'm working on machine learning model and tried to downsample WAV files with Python script, but it didn't work, so I made the simple version - script "resamples" WAV file from 44100Hz to the ...
1k views

### What additional inputs are required to convert dBFS to dB SPL?

It is probably very well known that dBFS cannot be directly converted to dB SPL without knowing other information such as the technical specifications of the microphone. The questions are: What is ...
423 views

### What causes the mismatch between a calculated sine wave and a measured sine wave?

Note: this question has been edited to refer to a sample that does not use dithering. I recently asked my first question on here, about what I saw in an uncompressed audio file written out as integers....
62 views

### Reconstructing a wave which interferes together with a second known one

Is it possible to calculate one of two interfering waves, if the interference (the sum) $v$ and the other wave (summand) $v_1$ is known? The waves have same frequency but may differ in phase and ...
35 views

### Formulas associated with Daubechies Wavelets D2, D3, and D4

I want to knom if there exist any actual formulas for defining Daubechies Wavelets D2, D3 and ...
189 views

### Inverting (spectrogram vertical flip) a signal of WAV file

What I need is to invert a signal (on spectrogram it would look like a vertical flip) of a WAV file. Actually, of a bandpass of a signal - from 500 to 800 Hz, for example. This image will perfectly ...
254 views

### Return list of wav files in folder that are clipped

Is there any method via python of any other means, to return a list of wav files in a folder that are clipped? I know that Adobe Audition can tell if a file is clipped, but I have to open up each file ...
1 vote
78 views

### Is the magnitude of the phase shift independent of the volume of the sound?

Sound waves can cause vibration of the particles/objects that are scattering/reflecting/emitting the light. Since vibration is spatial displacement, it causes a phase shift by affecting the value of &...
170 views

### Estimation of the attenuation of two waves on a linear sensor array

Context and objective I am trying to estimate the attenuation coefficients ($\alpha_u$ and $\alpha_v$) of two waves ($\overrightarrow{u}$ and $\overrightarrow{v}$). These waves propagate on a linear ...
1 vote
54 views

### Envelope of a series of pulsed signals [duplicate]

I need to record a series of pulse waves for an experiment. The recording is done via Software Defined Radio (GNU Radio). The pulse waves are modulated in such a way that the amplitudes of each single ...
74 views

### How to obtain the wave height "H" /wave period T from the spectral density S(f)

I have the equation of the power spectral density $S(f)$. I seek $(H,f)$ of each sinusoid which $H$ is the magnitude and $f$ is the frequency. How to calculate $H$ from $S(f)$? $S(f)$ is the spectral ...
72 views

### How to inject a 2D plane sine wave to the array of seismic sensors?

I've several sensors positioned at various points in the $X$,$Y$-Cartesian coordinate system, and I've experienced a problem to inject a planar Sine wave to the spatially positioned sensors, the ...
1 vote
20 views

### What is meant by discrete time plot with Whatsapp voice notes? [closed]

You might have noticed ,as shown highlighted in attached snap, whatsapp voice notes are bearing a discrete time plot Is it exactly referring to sampled(discrete time)version of waveform of actual ...
381 views

### Finding the mode of propagation of a progressive wave and the velocity of that mode

Injecting a sinusoid say, $Z = A \sin(k_x X + k_y Y - \omega t)$, $K = 2 \pi f/c$, for example, assume $f = 10$ Hz or $50$ Hz, and $c = 50$ m/s, now if I draw the 2D K-space plot with the following ...
381 views

### How are sounds recorded and reproduced (played back)?

Someday I have suddenly got wondered how sounds are recorded and reproduced. I searched a little bit but the information I got was composed of difficult words and contents, so I couldn't understand ...
111 views

### Why can't millimeter waves travel far [closed]

So I was digging around 5g technology, and apparently, many people say that high-band 5g can't penetrate buildings, trees, even rain. However, the atmospheric attenuation around 30 GHz does not seem ...
3k views

### How to extract the dominant frequency from the audio WAV file using numpy

So, I recorded this audio on my phone while I was running a tone generator on my PC at a frequency of 13Khz, now I want to extract this frequency which is dominant from the recorded ...
273 views

### Why does a wave composed of two waves have an FFT with only one peak?

I am trying to find a value from a given mathematical function whose input is supposed to be derived from FFT components. Essentially, I follow the procedure from  which assumes that a given sine ...
79 views

### Reflected wave in FFT?

I'm trying to determine the reflective coefficient of sine wave. This one paper suggests a method using Fourier analysis. Here, it suggests Incident Wave = a cos(kx + Constant1), Reflected Wave = a ...
1 vote
31 views

### Resources for the Basics on Signals and Electromagnetic Waves in the radio frequencies [closed]

What are some good books and videos, to learn about radio waves? For someone (me) who has never studied Math, Physics, or anything people generally consider ‘technical’.
172 views

### Wave Digital Filter Bridge-T Resonator implementation, gives expected cutoff frequency but incorrect gain and roll-off

Trying to implement the WDF in Fig 5(a) of this publication. The response of the ideal op-amp implementation is given by the black curve in Fig 7: Here is the plot I get when trying to implement the ...
163 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 ...
57 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 ...
246 views

1 vote
147 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 ...
109 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.
485 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 ...
1 vote
75 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 ...
516 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 ...
88 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. ...
847 views

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1 vote
845 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 ...
209 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 ...
1 vote
19 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?
128 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 ...
127 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 ...
1 vote
127 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). ...