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Questions tagged [sampling]

In signal processing, sampling is the reduction of a continuous-domain signal to a discrete-domain signal.

A common example is the conversion of a sound wave (x(t), a continuous-time signal) to a sequence of samples (x[n], a discrete-time signal).

A sample refers to a value or set of values at a point in time and/or space.

A sampler is a subsystem or operation that extracts samples, x[n]=x(nT), from a continuous-domain signal. A theoretical ideal sampler produces samples equivalent to the instantaneous value of the continuous-domain signal at specified sampling instances.

Source: Wikipedia.

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What is meant by "stochastic sampling"?

What exactly is meant by "stochastic sampling" and is it profoundly different from the regular Nyquist-Shannon sampling theorem? Is it related to sampling a stochastic process?
Phonon
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What are the advantages, if any, of derivative sampling?

In Five short stories about the cardinal series $[1]$, the author makes the following comment: Interestingly enough, Shannon goes on to mention that other sets of data can also be used to determine the band-limited signal--for example, the…
datageist
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Sampling of a continuous function: Kronecker's or Dirac's delta?

I've been reading some papers in signal proccesing and I'm very confused about the issue in the title of my question. Consider a continuous function of time $t$, $f(t)$, that I sample at uneven times $t_k$, where $k=1,2,...,N$. To me, it makes sense…
Néstor
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BandPass Signal Vs PassBand Signal

Am reading Rick Lyons - Understanding DSP book about Sampling. I have few doubts related to this chapter. what is the difference between Bandpass Signal and a Passband Signal ? Can somebody give an example for a Bandpass system which produces…
rajez79
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How replicas are formed in Frequency domain when a signal is sampled in Time Domain?

I know that sampling in one domian (time or frequency) gives raise to replicas in another domain (frequency / time). How replicas are formed? What is this Time domain periodicity and frequency domain periodicity here in sampling?
rajez79
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How to calculate sample times when the clock rate is not divisible by the sample rate

I need to sample an ADC at 4096 * 60 = 245760 times per second, but the system clock is 200 MHz. This gives a sample period of 813.80208333.... clock cycles. I've determined that I can achieve the correct average rate if I have 19 sample periods of…
Campground
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implication of sampling and reconstruction theorem

I am asking this question sorta as a surrogate for a friend at comp.dsp who posted a similar one. Even though I did it for a quarter century, laying out math (using "ASCII-math") is crappy, which is why I think the traffic at comp.dsp is in decline…
robert bristow-johnson
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Dealing with Random Errors in Sampling Rates?

I wonder what generalization I can make about what happens when I introduce some error in my sampler spacing. For example, If I sample once every second I would want my sampler to take a signal at 1s,2s,3s,4s. Unfortunately, my real world sampler…
Mikhail
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Should I sample at twice the bandwidth or twice the highest frequency?

I am confused about what rate I should sample at. I've heard 2 different ways: 1) Sample at twice the highest frequency 2) Sample at twice the bandwidth If I have a signal composed of just cosine, such as: $$x(t) = \cos(4 \pi t) + \cos(2 \pi t) +…
user44051
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Suitable sampling rate for triangle wave

I know this is a fairly simple question but I can't convince myself of the right answer. For a 5KHz triangle wave, being sample at Fs sampl/second, what's a suitable choice for Fs such that an accurate reconstruction of the cont. time wave can be…
dsp_yes
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What is the role of a LPF in oversampling?

Lets assume that a signal $x(n)$ is up-sampled by adding 1 zero between two adjacent samples to form a signal $y(n)$. How does a digital LPF give an oversampled version $z(n)$, with more data points? (As show in the image below) I know that the…
user29568
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What is the difference between the Point Spread Function and Sampling Aperture?

I've been told that the point spread function of a pixel is its distribution of intensity, while the sampling aperture of a pixel is its distribution of sensitivity. I'm a little unsure of what the difference between intensity and sensitivity is. It…
someguy
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Compensating for measurement errors

I have a system where I sample some data periodically (every 10usec). The shape of the data is triangle, in other words it linearly increases and decreases in time. (Both theory and practice are in agreement, I plot the ADC output and I clearly see…
Frank
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Ideal sampling - question about the 1/T scaling factor

Sources discussing spectrum of sampled signals (under 'hypothetical' IDEAL SAMPLING condition) show that the original message spectrum gets replicated at integer multiples of the sampling frequency. It's noticed that the sources show that the…
Kenny
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Locking on to a square wave signal with minimum oversampling

I'm designing a device that will have an IR photodiode connected to a low power microcontroller's ADC pin. At times, another device will be transmitting a 48KHz square wave, and I'd like to be able to detect when that is the case entirely in…
Nick Johnson
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