Shot noise Definition and 14 Threads

  1. F

    A Expression of Shot noise when expanding ##a_{\ell m}## coefficients

    I would like to arrive at the following expression for the quantity ##o_{\ell}## ( with "DM" for Dark Matter ): ##o_{\ell}=b_{s p}^2 C_{\ell}^{D M}+B_{s p}## with Poisson noise ##B_{s p}=\frac{1}{\bar{n}}(\bar{n}## being the average number of galaxies observed). the index "sp" is for spectro...
  2. F

    A Add factor Δℓ or Δℓ^2 in the variance for integrated Shot noise

    I have the following expression for an error on a Cℓ : ##\sigma(C_{\ell,X})=\sqrt{\dfrac{2}{(2 \ell+1)\Delta\ell \,f_{\mathrm{sky}}}}\left[C_{\ell,X}+N_{X}(\ell)\right]## where ##X## corresponds to spectroscopic/photometric shot noise and with ##\Delta\ell## is the bin width between 2 values...
  3. F

    A Expression of the mean and variance of spectroscopic Shot Noise

    Hello, I would like to know the right expression for the expression of variance of Shot noise in spectroscopic probe. Sometimes, I saw ##\sigma_{SN,sp}^{2} = 1/n_{sp}## with ##n_{sp}## the average density of galaxies, whereas my tutor tells me that ##\sigma_{SN,sp}^{2} = 1/n_{sp}^{2}## , so I...
  4. F

    Poisson distribution and Shot Noise

    My setup: I have the an LED (LED370E) in front of a photodiode (S12915-16R). The photodiode is connected to an ADC (DT5751) which has a counting functionality. The way it works is that it counts how many times the signal goes above a certain threshold and makes a histogram out of it. I know...
  5. A

    How Does Shot Noise in a Photodiode Lead to White Noise Characteristics?

    Not really sure where this belongs... But here goes: If you illuminate a photo diode it generates a current because electrons are being emitted from its cathode. Since each emission is however an independent stochastic process the output current will be subject to fluctuations, which can be...
  6. M

    Is It Shot Noise or Avalanche Noise in Your Circuit?

    I frequently see the following circuit being used as a noise generator: ... where the transistors are basic npn bipolar transistors. Some authors attribute the noise to shot noise while others say it is avalanche noise. How do I determine which is correct?
  7. O

    Signal to noise ratio for thermal and shot noise

    Homework Statement The output of a sensor which produces 10000 electrons is connected to parallel RC circuit with Resistance= 50 ohm, and the capacitance=10pF. Calculate the signal to noise ratio at temperature 300K. Homework Equations SNR= 10 log (power of signal/ power of noise) Or...
  8. M

    How Can I Reduce Shot Noise in a Phototransistor Audio Application?

    Citizens of Physicsforums. I would greatly appreciate your advice. I've been wrestling with a pesky noisy phototransistor for quite a long time, and am at wit's end. The sensor is being used to transuce an audio signal in the 1-5kHz range. Unfortunately the shot noise is introducing...
  9. N

    Photocurrent shot noise correlation function

    Hi I have stumpled upon the following expression for the correlation function of the photocurrent shot noise for a photodiode <\delta i(t)\delta i(t+\tau)> = \frac{e^2\eta}{h\nu}P\delta(\tau) where η is the quantum efficiency and P the power in the signal. δ(τ) denotes the Dirac delta, which...
  10. M

    Johnson and Shot noise the Frequency Term

    I am a bit confused over the frequency term that appears in Johnson and Shot noise formulae. What is this term? Is it bandwidth? Of what? In relation to say a photodiode, is it the range of frequencies being detected? And how would this relate to say a DC circuit which no frequency terms...
  11. M

    Johnson and Shot Noise at 20*C with 9V Battery and 100Kohm Resistor

    A battery of emf 9V, and negligible internal resistance, has a 100Kohm resistor connected across its terminals. What are the values of johnson and shot noise at a temperature of 20*C if the measurement bandwidth is 10KHz? At what temperature would the johnson and shot noise contributions to...
  12. E

    MATLAB Adding Signal and Shot Noise in MATLAB - MB's Question

    hello well I have 2 vectors in MATLAB each representing a signal+shot noise. I have to add them. Can anyone tell me what the signal noise ratio will be when they are added? thanks MB
  13. U

    Can You Combat Johnson Noise and Shot Noise in Instrumentation?

    I was wondering if someone could give me some ways to combat Johnson noise and shot noise. Thanks
  14. C

    What is shot noise and how is it estimated in galaxy surveys?

    I am reading about galaxy surveys. I want to know what is shot noise ? how we estimate it into real and Fourier space ? I am basically reading astro-ph/0503603 & astro-ph/0503604. I am not able to solve exercise 4, 5, 6. I will be thankful, if anybody can provide me some reference.
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