Questions tagged [ultrasound]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
9
votes
1answer
977 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. ...
7
votes
5answers
10k 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 ...
5
votes
2answers
466 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 ...
3
votes
1answer
496 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 ...
3
votes
1answer
172 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 ...
2
votes
1answer
417 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 ...
2
votes
2answers
240 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 ...
2
votes
1answer
129 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 ...
1
vote
1answer
349 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 ...
1
vote
1answer
718 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 ...
1
vote
2answers
2k 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 ...
1
vote
1answer
74 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{...
1
vote
0answers
15 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 ...
1
vote
1answer
710 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 ...
0
votes
1answer
770 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. ...
0
votes
1answer
154 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/...
0
votes
0answers
17 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 ...
0
votes
2answers
41 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/...
0
votes
1answer
20 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/...
0
votes
0answers
21 views

Matched filter correct peak detection [duplicate]

I am working with ultrasound signals with frequency 100 kHz. Chirp signals with bandwidth 16 kHz are being modulated with 100 kHz and then transmitted via one ultrasonic sensor. With another ...
0
votes
0answers
154 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 ...
-1
votes
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 ...