Questions tagged [noise]

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Most sound proof earmuffs in the world

What soundproofing material can I replace the foam in my Sthil earmuffs with to block out leaf blowers completely. I mean the absolute highest power blackout capability possible. Crazy ideas welcome, ...
Julian's user avatar
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Calculating noise floor level and SNR

I have N samples of a baseband IQ signal that I took from an SDR (Pluto) with a certain fs (BW = fs). How can I accurately calculate the noise floor level of that signal in dBm, SNR in dB and Peak To ...
Daniel Cohen's user avatar
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Maximize SNR of RGB IR light-sensor for certain LED wavelength

I have a light-to-digital sensor (TCS34001) that measures intensity in four different bands (R, G, B, IR) and a red LED (ASMT-MR00-AHJ00) that I want to detect. Their spectra look like this: (ignore ...
gnarflord's user avatar
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How can I reduce noise from pushrods in an assembly without using grease/oil?

I have an assembly which consists of a row of vertically-oriented nylon pushrods (each 5/16" in diameter, colored green in the attached pictures), and two black pieces of laser cut delrin ...
user10264746's user avatar
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2 answers
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Noise issue - reduce vibrations

I would need the help of an engineer expert in sound. I live in a very noisy city close to a club. They make live music till 3 AM and I can hear them even when wearing earplugs. Now, here is my issue. ...
Quant91's user avatar
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2 answers
46 views

Squared telecom parameters

I observe that some telecommunication parameters are squared like noise power is $σ^2=-95\text{ dBm}$, and the amplifier coefficient $η^2=20\text{ dB}$. What is the meaning of the square? Can I remove ...
Mary Dona's user avatar
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3 answers
95 views

Releasing compressed air with the loudest pop

Due to the dry summer I've been thinking about theory of making cracker/banger without fire. Would connecting a nozzle (de Laval?) to quick release valve from small cylinder with the pressurised air ...
Filip Matyja's user avatar
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32 views

Freestanding wood frame inside masonry shell for noise?

I'm a lay neighborhood advocate, not an engineer. Proposed is a three-storey multi-family housing project adjacent to an airport. A concern is that noise pollution will create higher tenancy turnover, ...
Michael Malak's user avatar
1 vote
0 answers
46 views

How loud can an induction hob be?

People that are cooking food with induction will occassionally encounter loud noises from the hob. There can occur a high-pitched whining sound when heating the pots and/or pan. As I searched the ...
kryomaxim's user avatar
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What to do with the high dv/dt on bridge H?

I have an H bridge, with a 540V DC link. There is a high level of noise induction across the board (even though all circuits and sources are isolated). Bridge H has drives that provide dual power (+...
percisi's user avatar
1 vote
2 answers
195 views

How do I remove outliers in measured sound pressure levels data?

I have measured sound pressure levels (24 h sampling at 25600 Hz) data for many days. The focus of measurements was on road noise, which is a dominant source of noise in the measurement setting. ...
khajlk's user avatar
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2 votes
1 answer
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Active noise cancelling headphones - How fast does a digital signal processor have to be to perfectly cancel out noise with an inverted signal?

How fast does a digital signal processor have to be to perfectly cancel out noise with an inverted signal? Is it possible for a digital signal processor react so fast?
water castle's user avatar
1 vote
1 answer
2k views

How to add a Gaussian noise signal with zero-mean in a given data set?

I have a real-time velocity measurement data set in a excel (.xlsx) file. I want to add the Gaussian noise signal with zero mean in this real-time data to create three set of pseudo measurements. ...
S.Prabhu's user avatar
1 vote
0 answers
352 views

Active noise canceling for CNC enclosure

this is my first post here! I wanted to share my ideas for this and get some input on them. My parents were kind enough to let me put a cnc machine in the loft. (shapeoko 3 xxl) In order to make them ...
Perch Perkins's user avatar
2 votes
2 answers
205 views

How to convert the velocity field to a pressure field for obtaining the sound level?

I am studying jet mixing noise and I am given a velocity field, with $V_x$, $V_y$, $V_z$ in the Cartesian coordinates. I wanted to know if there is a method by which I could find some information ...
fidafa123's user avatar
1 vote
0 answers
40 views

Understanding the RMS noise for a given bandwidth

I would like to ask a technical question regarding the current source Keithley Series 2400 Model 2450. I am looking for a high stability current source capable of feeding some Hall probes with a ...
jeb's user avatar
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3 answers
171 views

How do AC/DC Adapters (Wall Wart) prevent AC Noise Coupling to DC?

I am wondering if AC noise (EMI) gets coupled to the DC side of the AC/DC adapter, what are the design methods used to isolate AC noise getting coupled to DC output in an AC/DC adapter. What are the ...
Nil_2018's user avatar
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4 votes
1 answer
177 views

allan-variance noise terms of MEMS accelerometer

Specific noise terms are given in datasheets of MEMS sensors. In example the specification of accelerometer contains information about random walk and in some cases the bias instability. Both ...
annemeler's user avatar
2 votes
3 answers
202 views

Why does audio equipment buzz/humm when a long signal cable is used and how do I eliminate it?

I have two 5.1 speaker sets, one in the front and one in the back of my living room. I have connected them together with an "audio wire" (non-shielded unfortunately) that's 12 meters in length. Since ...
Gizmo's user avatar
  • 123
1 vote
1 answer
103 views

Linear actuator with low vibration and low noise

Which kinds of linear actuators offer the lowest levels of noise and vibration? I am looking for an actuator with these properties that can push a load vertically on the cm scale. Velocity, accuracy ...
Elon Musk's user avatar
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2 votes
2 answers
823 views

How do I calculate hourly LAeq sound pressure level using 1-mint LAeq values?

I have continuous A-weighted sound pressure level (SPL) values at 1 minute time resolution (LAeq,1min). I would like to calculate ...
khajlk's user avatar
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0 votes
1 answer
101 views

Noise sensitivity transfer function

Consider we have a second order system (plant) described by the following transfer function: $$ P(s) = \frac{b_0}{s^2+a_1*s+a_2} $$ which is controller by a PD-controller: $$ C(s) = K_p+K_ds $$ ...
Teo Protoulis's user avatar
1 vote
2 answers
1k views

How to reduce oscillations (rapid changes of control signal) when controlling a real system, which occur due to noise in measurement from sensors?

I have a real mechanical system (ball & beam) which I want to control. The system is approximated by the second order transfer function: $$ T(s) = \frac{b_0}{s^2+a_1s+a_2} $$ and in state-space ...
Teo Protoulis's user avatar
1 vote
0 answers
28 views

Meaning of SNR in Instrument Specifications

I am evaluating the specifications of an FTIR instrument (Bruker Vertex) and came across the following statements/items: Signal-to-Noise 5 sec sample, 5 sec reference: >10,000:1 (<4.34 x 10-5 ...
bebissig's user avatar
1 vote
1 answer
92 views

Sound level emissions (IEC 60704-1) spectrum?

I have a very noisy air conditioner that have a 10kHz peak at 75 dB, the rest (fan/compressor/pump) are under the regulation limit. I would like to understand what is the measurement spectrum. I ...
nowox's user avatar
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