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Questions tagged [noise]

22 questions
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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 quantities are determined by computing the allan varianz…
annemeler
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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
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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 relating to the sound level produced from the…
fidafa123
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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 I did this, the speakers started buzzing/humming…
Gizmo
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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 internet, there where no data on how high the noise…
kryomaxim
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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. However, there were occasional "disturbances", such as…
khajlk
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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. Could you please tell me how to do this in the excel…
S.Prabhu
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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 nominal current of 10 mA. According to the 2450's…
jeb
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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 and max force are secondary. I'd be very glad for…
Elon Musk
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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 LAeq SPL at half-hourly and hourly resolutions using these values. Can someone suggest on how this could be achieved?
khajlk
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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 form: $$ \dot{x_1} = x_2 $$ $$ \dot{x_2} =…
Teo Protoulis
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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 AU noise) peak-to-peak @ 2,000 cm-1, 4 cm-1 spectral…
bebissig
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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 think 10kHz is out of the measurement spectrum, but I…
nowox
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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. If I don't lay in bed, I barely feel vibrations.…
Quant91
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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 it with mathematical calculations?
Mary Dona
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