{ "cells": [ { "cell_type": "code", "execution_count": 18, "metadata": { "ExecuteTime": { "end_time": "2021-09-27T19:15:08.678463Z", "start_time": "2021-09-27T19:15:07.521881Z" }, "tags": [ "remove-cell" ] }, "outputs": [], "source": [ "import numpy as np\n", "import matplotlib.pyplot as plt\n", "from scipy import special" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Lecture 2: Noise processes and measurement sensitivity\n", "\n", "```{admonition} Expected prior knowledge\n", ":class: tip\n", "Before the start of this lecture, you should be able to:\n", "\n", "- write down the relation between the autocorrelation function and the power spectral density\n", "- describe the power spectral density of white and 1/f noise processes \n", "```\n", "\n", "```{admonition} Learning goals\n", ":class: important\n", "After this lecture you will be able to:\n", "\n", "- describe the Poissonian and Gaussian probability distributions and argue when they arise\n", "- relate the noise power spectral density of a sensor to its ability to detect a small signal\n", "```\n", "\n", "Where does noise come from?\n", "\n", "In general, noise is caused by processes we don't know about, or at least don't \n", "know enough about to predict. A good example of this is the Brownian motion\n", "of a particle in a liquid, which for the right type of particle, one can even\n", "see in a microscope.\n", "\n", "Due to random collisions with molecules in the liquid, the particle experiences\n", "a randomly fluctuating force: it experiences \"force noise\", and undergoes random\n", "motion in time.\n", "\n", "[