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Questions tagged [ultrasound]

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How to solve the overlapping problem in ultrasound

I am working on ultrasound signals, which in general are narrowband and short duration, however, my aim is to use spread spectrum signals that give wider bandwidth. The problem with such is that upon ...
Film StripStar's user avatar
1 vote
1 answer
69 views

How to extract pressure values from a WAVE file?

Possible a duplicate but I could not find a direct answer. I used a sound card (Focusrite, at 96 kHz sampling frequency) connected to a calibrated hydrophone to record an ultrasonic signal, with a ...
Sixx's user avatar
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0 answers
21 views

Need help to calculate phase velocity in subsequent echoes

I have the response signal of a piezoeletric transducer. I'm trying to acquire the phase velocity of the echoes I'm receiving. The resonancy frequency of the transducer is 5 MHz. I'm using an ...
Lucas Albuquerque's user avatar
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0 answers
25 views

How a fish sonar is built and signals from sensors processed?

How a fish sonar is built and signals from sensors processed ? There are $50 fish wireless sonars on the market. I would to buy one but need to know how it works, what is a number of sensors and if ...
darius's user avatar
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1 vote
1 answer
104 views

what is the correct order of applying a nonlinear operation and downsampling (with anti-aliasing)

In UltraSound imaging, after beam-forming and obtaining the envelope, Log-compression which is a non-linear operation and scan conversion which is a 2D interpolation (with inherent down-sampling) is ...
Mohammad M's user avatar
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1 vote
1 answer
143 views

Ultrasonic TDoA / ToA Measurement?

I am trying to make an ultrasonic flowmeter. The device has two ultrasonic tranducers (resonance frequency of about 200kHz) that sample one ultrasonic signal in the upstream directon and then ...
dsparateRealities's user avatar
0 votes
1 answer
307 views

How is $-6$ dB pressure amplitude is the same as FWHM?

I keep reading many literature, and in most cases $-6$ dB is referenced as the full width at half maximum (FWHM). Mathematically, how is that possible from the definition of dB?
Katherin Romanova's user avatar
1 vote
1 answer
285 views

How to make ultrasound audible?

Because of interesting spectral phenomena, I would like to shift the >20kHz content of my audio recordings to audible frequencies, so that I can listen to it. I tried the Audacity pitch correction ...
VGF's user avatar
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0 answers
1k views

How to scale audio signal from PCM data to a dB SPL value?

I've got a set with MEMS microphones that measure audio signals at ultrasonic frequencies. The MEMS microphones have a PDM output which is then converted into PCM (this is necessary to allow for a ...
dg1271's user avatar
  • 1
1 vote
3 answers
838 views

Phase of matched filter for chirp signals

I am using the following system: Ultrasonic chirp signals with central frequency 100kHz are being transmitted using ultrasonic sensor. After the transmission through the medium(air/solid/liquid/...
Deanna77's user avatar
0 votes
1 answer
45 views

Direct path and reflections of ultrasound transmission

I am using the following system: Ultrasonic chirp signals with central frequency 100kHz are being transmitted using ultrasonic sensor. After the transmission through the medium(air/solid/liquid/...
Deanna77's user avatar
-1 votes
1 answer
60 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 ...
Lkaf Temravet's user avatar
2 votes
2 answers
481 views

Audio Steganography: Inaudible Audio Watermarking for Source Identification

What is a relatively inaudible audio watermarking technique to overlay a broadband audio signal on top of playing music without analysing the music for low-bitrate source identification? Ideally ...
Petrus Theron's user avatar
0 votes
0 answers
235 views

How to remove echo/reflected-sound caused by stationary objects when building a ultrasound based radar

I am emitting ultrasound with a speaker and am trying to track moving objects with a microphone array by detecting doppler shifts. I have succeeded to detect movement. However, to detect the direction ...
Deep Mind 's user avatar
11 votes
5 answers
25k views

Why is Scipy implementation of Hilbert() function different from Matlab implementation of the function?

I am trying to fit Hilbert envelop to a high frequency ultrasonic signal of frequency 250 KHZ and sampling rate 12000000. Raw signal looks like below: . I used hilbert() function from scipy.signal ...
Spandyie's user avatar
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2 votes
1 answer
214 views

Changing the number of cycles of an sinusoidal input signal

Imagine we have an ultrasonic sensor that transmits a multiple cycles of sinusoidal signal/waveform that can travel up to a specific distance/range. Can we achieve more distance coverage using more ...
S Fateri's user avatar
  • 316
5 votes
2 answers
560 views

Are Amazon Echo ads embedding an ultrasonic signal to suppress recognition of the Alexa keyword?

Related to High audio frequencies in television broadcast My cell phone samples at 48000 samples/sec so the FFT app I installed can only detect frequencies up to 24 kHz. If anyone has an audio ...
Graham Toal's user avatar
0 votes
1 answer
1k views

Determine Sound Intensity in SPL

I am recording ultrasonic sound using "Earthworks M50 50kHz Measurement Mic" and the sound card is "Rolando Quad-Capture USB 2.0 Audio Interface". The recording was done using Matlab into a wav file. ...
Ahsan Raza's user avatar
1 vote
2 answers
3k views

Extracting sound pressure from wav File

I have recorded an ultrasonic wave from a microphone using MATLAB command. After plotting that recorded wav file, the graph shows the amplitude between $1$ and $-1$. Can anyone tell that what is ...
Ahsan Raza's user avatar
1 vote
1 answer
115 views

How to create a control loop using a 100Msps digital signal as input

I would like to know what type of microcontroller should I buy for this control loop task. Scenario: I have a digital signal coming from the following equipment: $\boxed{\text{Ultrasonic}\\\text{...
Hangon's user avatar
  • 111
1 vote
1 answer
429 views

Best DSP algoritms for ultrasonic background noise cancellation

I am looking into detection of pressurized gas leaks by means of the broadband hissing sound (white noise) generated from pressurized leaking gas. The instrument will have a broadband microphone ...
mtolesen's user avatar
1 vote
0 answers
17 views

Acoustic characteristics of thoracic diaphragm

I am looking for any kind of information about the acoustic characteristics of the thoracic diaphragm. In particular, I'm looking for characteristics which will allow to differentiate it from other ...
Arrow's user avatar
  • 243
0 votes
1 answer
224 views

What are the units of amplitude of my ultrasonic recording equipment

I'm not familiar with the topic of sound. I have ultrasonic audio recordings sampled at 250kHz (16bit) in WAV format. The equipment used to record them is linked here: http://www.avisoft.com/usg/...
user3120554's user avatar
9 votes
1 answer
1k views

Ultrasonic signal detection

I have created a fairly simple TDOA system that uses ultrasonic signals emitted from two speakers to geolocate (relative to the speakers) mobile phones. The two signals are separated by frequency. ...
Jim Clay's user avatar
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3 votes
1 answer
233 views

Underwater Acoustic Positioning

I have to develop an underwater positioning system which has to determine the position of a ROV. Four buoys will be placed on each corner of a swimming pool. Each one of these buoys will be equipped ...
Seitam's user avatar
  • 133
3 votes
1 answer
518 views

Ultrasound Signal Processing Methods

I am sending 6.6Vpp square wave across a narrow-band, 40 kHz Transmitter to a narrow-band, 40 kHz Receiver. I want to find a very accurate distance between the two (sub millimeter). My assumption so ...
user2525288's user avatar
1 vote
1 answer
870 views

Upsampling signal for cross correlation

I am recording a 17khz signal at a sample freq of 44.1khz. I want to perform cross-correlation between the received and transmitted signals for calculating TDOA. But when I do xcorr, the results are ...
BaluRaman's user avatar
  • 689
1 vote
1 answer
806 views

Time delay estimation using ultrasound

I have a sound source that generates an ultrasonic pulse. I have two microphones seperated by a distance which are at a distance from the source. I want to find the time delay of arrival of the ...
BaluRaman's user avatar
  • 689
2 votes
1 answer
471 views

Wavelet signal analysis for ultrasound echo

I am new to the wavelet field, and I am working with ultrasound signal. For my study, I needed to measure material using the pulse echo reflection method. Basically, when the transducer transmits ...
Mr.Own's user avatar
  • 21