# Questions tagged [noise-spectral-density]

Anything related to the noise spectral density, i.e. the function representing how the power of the noise signal is distributed among its frequency components.

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### A-Weighted Noise Power Calculation

Can anyone please show me how to calculate the A-weighted noise power of a noise source. Consider the case of a resistor having a spectral density of 4kTR. What is the A-weighted noise power of this ...
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### Noise Fluctuation with MAX40660

I am currently implementing MAX40660 as a high speed TIA amplifier. In the process of testing the basic functionality of the circuit, I have implemented a pcb design similar to the evaluation kit. ...
801 views

### Noise density in 1/f region

The datasheet of the ADR1000 voltage reference specifies the 1/f noise density as 30nV/sqrt(Hz) at 10Hz and 300nV/sqrt(Hz) at 0.1Hz. Given that this is the 1/f region of the voltage reference, how can ...
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### Noises are measured over a bandwidth. Is 50Hz and 900Hz noise the same at 1kHz bandwidth? [closed]

They say noise is over a bandwidth. At a bandwidth of 1000Hz. Is the noise at 50Hz and 900Hz similar? If yes. Please made a quick drawing how the noise at 50Hz and 900Hz look like roughly so I can ...
• 847
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### Why different noise terms are read at specific sampling interval in Allan Variance plot?

I was trying to identify Quantization Noise, Angle Random Walk, Bias Instability, and Rate Random Walk from Allan Variance plot which as Allan deviation on y axis and Sampling Time Interval ...
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1 vote
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### Impact of laser current source noise on RIN (relative intensity noise)

I am trying to specify the noise requirements for a constant-current source that would drive a diode laser with a certain relative intensity noise PSD. Lasers typically behave as forward-biased ...
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### How to properly compute noise power spectral density?

I am confused about two different definitions of Power Spectral Density (PSD) that I have seen online. The first comes from the National Instruments LabVIEW documentation (1):  PSD = \frac{PS}{\...
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### Simulating Gyroscope with ARW, BI, and Spectral Density Using Physical IMU Data

I'm currently working on a state estimation project that relies on IMU data. While I have access to a physical IMU, I'd like to simulate gyroscope data with specific parameters, including Angle Random ...
235 views

### Noise Figure in LTSpice

I'm simulating an LNA from a paper. It's using HBT BiCMOS technology an one of the things the paper shows is the simulation of NF in range of 3GHz to 10GHz. I'm trying to replicate the simulation with ...
1 vote
236 views

### Noise scaling in a current source

I have a bunch of constant current sources in my lab: some are laser diode drivers and some are DC power supply units that have a constant current mode. I've known from prior experience that some of ...
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### Low noise virtual ground, voltage reference or LDO + op amp?

I'm doing some sensitive signal measurements in 1~10kHz range where I amplify and filter (multiple active stages) a small voltage signal by hundreds ~ thousands of times and then sample it. A negative,...
• 185
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### How do you simulate resistor noise with LTSpice?

Is there a way to setup a resistor noise source (Johnson/Thermal noise)? I want to experiment with add a Johnson/Thermal noise source to a resistor for test in LTSpice, but not sure how to configure ...
117 views

### Random telegraphic noise and Lorentzian noise power spectral density

Following the example of the Lorentzian noise power spectral density shown above (ref), I would like to clarify the following: In the first figure (labeled by (c)), May I please know why the constant ...
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### How does one calculate output voltage noise of a current output DAC?

I am using a current output DAC connected to a voltage reference and a transimpedance amplifier. I know the noise characteristics of the voltage reference and the amplifier. The DAC simply lists "13 ...
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### Does the profile of phase-noise power spectrum density (PSD) vary with time?

I will promptly provide any detail or revise my question aimed at any feedback. Does the profile of phase-noise power spectrum density (PSD) vary with time? The conclusion may be that it won’t ...
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### Johnson-Nyquist noise for a lossy inductor?

In searching the internet for thermal noise on an inductor and I'm not finding much on the basics for a real lossy inductor. I'm interested in thermal noise for a fixed inductor in a surface mount ...
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### The mean value of phase noise as a stochastic process

What is the mean value of phase noise as a stochastic process? Where can I get a theoretical analysis of this topic?
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### Noises of switching power supply

I made a switching power supply (input: 24VDC, output: +-15Vdc) for LEM (current sensor). Noises of the power supply caused the output of LEM to become a bad waveform, but I don't know how to ...
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1 vote