Sampling Definition and 207 Threads

I have been given a data and asked to state the sampling interval Heres what I know The data has a value generated for each month of the year, I have calculated a period of 11 years. Now I know the formula: 2PI/omega = number of samples per period So will Omega = PI/66

I designed four different transfer function to differentiate and accumulate a given function. In my example, the given function is sin() between [0, 6*PI]. Dashed blue line: The original input function (i.e.; sin(t)) Red line: Integration of sin(t) with initial value of -1.0. (H(s) = 1/s)...

I am curious how does the wavelength of light let's say 800nm/s collected by a photodiode results from the saturation of the plate 1mm. sq. I have this photodiode from a cdrom and it has 6 legs, two do not have a bias-junction, the other four do, and the collector is slightly greenish. I...

Hi. Consider the following state space equation x_k = f(x_{k-1},v_k) where f(.) is a nonlinear function and v_k is a white Gaussian noise (independent of state). I want to generate samples according to p(x_k | x_{k-1} = x_{k-1}^i) for a particular x_{k-1}^i. I've seen people generate...

[MODDERATOR NOTE: The OP has a follow up question. I added it to the end of this thread.]

Hi, I am trying to answer a question for an assignment, but am convinced that it doesn't make sense. Please see here: http://img813.imageshack.us/img813/1585/qst.png My problem is with Plan 2 in the question. The probability of selecting any of the 5 elements on the first selection is...

I am considering http://en.wikipedia.org/wiki/Hong%E2%80%93Ou%E2%80%93Mandel_effect" Wikipedia explanation says that "Therefore, when two identical photons enter a 50:50 beam splitter, they will always exit the beam splitter in the same (but random) output mode." And yet before this it...

Identify the sampling technique used to collect the data. Nursing supervisors are selected using random numbers in order to determine annual salaries. Choose one answer. a. Random b. Stratified c. Systematic d. Cluster e. Convenience This one is DESTORYING me.. EDIT: Please...

Hi, Suppose I have N iid samples from a distribution q, and I want to estimate another distributin, p, using those samples (Importance Sampling). By "standard importance sampling", I mean the case where samples (prior samples. i.e. samples from q) have equal weights ( w_i = 1/N ). In...

i have a population of items and i calculate how similar each item is to the rest of the items in the population. i store these values in a symmetric nxn similarity matrix. when i look at the distribution of scores, they follow a beta distribution -- most similarity scores are close to 0 (the...

Sampling theorem says that we should sample at least at a double rate than the bandwidth of the signal : Fs>=2B. Ideally Fs==2B e.i. oversampling is unnecessary. However, there's always noise present in the signal. Hartley's theorem connects the SNR with the bandwidth and the sampling rate for...

Homework Statement there are 30 red balls, 30 white balls, and 30 blue balls in a container. you draw 10 of them, without replacement. what is the probability that at least one color won't be selected. Homework Equations The Attempt at a Solution i've been working on this one for...

Hey folks! :smile: I am working through my text entitled Probability and Statistics for Engineers and Scientists by Walpole et al. I am getting a little stuck on their lackadaisical derivation of the standard deviation of the means. Perhaps I can get a little guidance here by talking it out...

I want to use this method to evaluate a triple integral that is otherwise impossible (not elementary). The region is the unit sphere. The Monte Carlo method sounds simple, but if I were to use MATLAB to do this, how would I pick my random sample points so that they are INSIDE the region...

I used Audacity to generate a 5500Hz tone at a sampling rate of 11025. This is the result: To me this appears to be a tone at a frequency of (11025/2) with oscillating amplitude rather than a frequency of 5500. The tone also sounds like it looks. It has audible oscillations in amplitude. At...

Hey guys, I'm just curious to know, why is it important to sample the air above and the water in the swimming pool for the chlorine level...and I mean, is there a technique which involves potassium iodide and a pipette? Thanks!

Hi, I tried sampling s(t)=sin(400\pi t) + 0.5cos(12000\pi t) at 10000Hz (below the Nyquist sampling rate) in MATLAB and plotted the spectrum, I found that it had frequencies at +-200Hz (same as the continuous signal version) and +- 4000Hz(instead of 6000Hz in the...

Hi all, I have used Metropolis-Hastings rules in a Markov Chain Monte Carlo (MCMC) algorithm for a few months now. I feel quite confident with this method and I use it frequently for fitting various model parameters to observational data. Already I feel that computational time is really...

Homework Statement x(t) = 3*sin(1000*pi*t) Suppose that the signal is sampled at a rate of fs = 2000Hz. What is the discrete time signal obtained after sampling (i.e., the signal expressed as a function of sample number n, x[n]) What discrete time frequency, f-hat will the signal x[n]...

Homework Statement A sample survey interviews an SRS of 267 college women. Suppose (as is roughly true) that 70% of all college women have been on a diet within the past 12 months. Use a Normal approximation to find the probability that 75% or more of the women in the sample have been on a...

Homework Statement Given a ramp function x(t) = t*heaviside(t) with the known z-transform ( z / (z-1)^2 ). If the time-domain signal has been delayed by 2 seconds, then sampled with an unknown sampling rate (T). How could I get the z-transform (one-sided) for the discrete signal, for any values...

I have been puzzling over this problem for about a week now and cannot find the answer. In my opinion it is very theoretical, but I know I ma not the best mathematician on here so maybe someone else could look at this. Thank you.

hello everyone, I have an exam question about sampling frequency. Actually i really don't get the concept. I have limited sources. Question: Bandwith of x(t) 10 kHz y(t) obtained modulating x(t) with a sinus wave with frequency 30 kHz. y(t) sampled a) What is the sampling frequency...

Hi! I'm trying to write an algorithm that performes Importance Sampling Monte Carlo integration. I found some info about it, but I have trouble understanding how it actually can be implemented. Let f(x) be the function we want to integrate and p(x) the non-uniform probability...

The Fair Sampling Assumption, as commonly discussed, is implicit in Bell tests: As long as detection efficiency is less than 100%, the observed photon pairs are a representative sample of the total universe of emitted pairs. At this time, no Bell test has satisfactorily closed both the Fair...

Hi, y'all! I'm trying to figure out how to do this MATLAB project for school. We're required to read in an image and then sample random regions(square, matrix-shaped) of it. I read in the image and it is formed by a lot of numbers(pixels?), and I determined how to generate a random...

I am wondering why there are no discussions about correctness of fair sampling assumption in photon entanglement experiments so I would like to start one. Bell's inequalities are derived considering all emitted particles. But in real photon entanglement experiments only portion of emitted...

Okie, I am confused. What is the difference between Variance of Sampling Distribution VS Sample Variance? Let me take a shot first... 1.) Sample Variance is just the variance of the sample, like u have 5 objects from a pool of 1000 objects... the sample variance is just the variance of the...

Homework Statement A box contains 5 keys, only one of which will open a lock. Keys are randomly selected and tried, one at a time, until the lock is opened (keys that do not work are discarded before another is tried). Let Y be the number of the trial on which the lock is opened. What is the...

Why is the frequency spectrum of a sampled signal replicated? We have a Low pass filtered signal sampled well above nyquist rate. I can't understand why the spectrum is replicated.

Okay... this is a really simple question but I am pratically going nuts over it I can't sleep, I've been looking at it for like 12 hours, googling and wiking over it I am going crazy... Okie... Suppose I have 4 numbers, 0, 2, 4 and 6 and I grab 2 random ones with replacement... so I have...

Can we synchronize n samplers so that the system is being sampled at 1/n Planck time? What could we tell about the data values between two adjacent samples?

Hello, I have a question regarding fft's. My experience with working with Fourier transforms is pretty much limited to transforming contrived functions pen and paper style. But now I need something and I think the fft is the appropriate tool, but I'm having a hard time understanding some...

Hi, I have a project due that has to be done in Simulink. I am somewhat familiar with Simulink, but some things don't make sense to me. First off, What determines the time step between each iteration? eg. when you have a clock in the model, what determines the change in time from one...

Homework Statement Let X1,X2,...X10 be independent normal random variables with mean 10 and std dev 4. Let Y = X1+X2+...+X10. Let X be Y/10. What is P(X < 8) Homework Equations E(X) = 10 and Var(X) = 42 / 10 = 1.6 std dev of X = 1.6.5 = 1.26 The Attempt at a Solution To convert...

How come these two functions are used interchangebly? A sampling function is supposed to be a square wave with a very small duty cycle, but at least the height is still finite. A delta function has infinite height and zero width. It seems like both square wave and dirac train are used as...

Good day I'm wondering how to sample powder that is flowing through a pipe under vacuum. Which systems can be used for this? I have a DN300 pipe under slight vacuum (ranging -500 mbarg to -100 mbarg). The sampler should be connected to the pipe. These are the process conditions of our...

Let's say we have a given probability distribution. We sample two random numbers from this distribution, say x1 and x2. What is the probability that x1 > x2? Is it always 0.5? Does it even depend on the distribution? Sorry if it appears trivial. I just can't seem to wrap my mind around this...

Hi, I am struggling with a problem and do not know how I should approach it. I went to a baseball game with my son, where I bought him a packet of M&Ms. While eating the candy, my son asked me what color most of the M&Ms are. At first, I intended to tell him that there are equal numbers...

Hello all, Once again, I visit to pick your brains with the hope of enriching my own. This time, however, you get an opportunity to beat me up a bit, if appropriate. I don't mind paying the price. I wrote an article for this particular site that I expect will whip up a bit of controversy...

http://s188.photobucket.com/albums/z65/liznbren/stuff/?action=view&current=envelope.jpg" If I sample at just fractionally above the Nyquist rate, and I obtain a sequence as is shown in the linked image, is it reasonable to expect perfect interpolation (say with a Sinc function ideally) as it...

The process known as sampling in reference to music is as follows: A device called a sampler is used to convert an analog signal representing sound waves into digital information. This digital information is called a sample, artists often use samples in their music. however, this not the only...

Can someone define the process of digital sampling for me, perhaps a website with some info on it. I'm writing a term paper and I keep running into sampler adds, but no concrete facts. What is the function of sampler? I'm referring to a device that turns an analog recording into a digital...

Homework Statement Say I have a spike at some frequency from a Fourier transform (power spectrum) of a waveform that I'm sampling (sine wave at 10Hz in this case). If I decrease the sample rate what should happen to the appearance of the spike? What about increasing the sample rate? What...

I understand that it was Nyquist who proved that a channel of bandwidth B can transmit at a baud rate of 2B. Also, Shannon, about 10 years later showed that if a signal is sampled at a rate of at least 2B, where B is the bandwidth of the bandlimited signal, then the signal can be reconstructed...

Hello, This is the same type of question as the one I just posted before. This time I have obtained an answer and would really appreciate it if someone would check my reasoning: Suppose a signal x(t) has a Nyquist sampling frequency \omega_s . Compute the Nyquist sampling frequency for the...

Here's my question: Suppose a signal x(t) has a Nyquist sampling frequency \omega_s. Compute the Nyquist sampling frequency for the following signal in terms of \omega_s: x(t) + x(t-1) Well my first thought was, let's see how the spectrum of this new signal compares to that of the...

We are considering a system in which the input signal x(t) is multiplied by a periodic square wave s(t) in order to produce an output w(t). The input signal is band limited with |X(j\omega)| = 0 \ \ \textrm{for} \ \ |\omega| \geq \omega_M , where \omega_M is the bandwidth. We are supposed...

Hiya guys, I just have what I'm sure is a simple question about statistics, but I can't seem to find it anywhere ... I was wondering, when finding the standard deviation of a sample mean, why do you divide the population standard deviation by the square root of n? I'm not really sure why...

I need some online source . explaining how do we take a DNA sample from body cells.Preferably in a more advanced language .