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

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Spectral analysis of a time series with missing data points

I use a PC to record time series of some physical property. The problem is that, for some reason, I did not record the time series as a whole, rather I record first segment, then second, third, etc. ...
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64 views

What is the maximum frequency that can be captured by a given sampling rate?

Let's say that we want to digitally sample an analog signal and have a sampling frequency of 8000 samples/second. Usually the maximum frequency that can be captured is the half of the sampling ...
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58 views

how to solve the sampling rate conversion problem

I am trying to improve my DSP knowledge and this problem is too much for me. I am trying to solve following task: this is not a homework. any help will be appreciated.
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47 views

How is functional analysis linked to digital signal processing [on hold]

I have run into several documents that discuss the importance of functional analysis to digital signal processing especially in the domain of sampling and compressive sensing. Yet I have not seen ...
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52 views

Why band-limit a signal?

A Band-limited signal is defined as a signal whose Fourier Transform is zero above a specified frequency. Shannon Sampling Theorem is also stated for a strictly band-limited functions,i.e, "For a ...
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15 views

Sending a Filtered vs Non-Filtered speech over a Communication Link

To send a $10 \, KHz$ bandwidth of speech (Non Filtered speech), Nyquist criteria says that sampling duration should be $50 \, \mu s$. While for a $4 \, KHz$ bandwidth of filtered speech, sampling ...
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34 views

Nyquist Criterion in higher dimensions

I was just wondering if there were any "obvious" resources, papers, or textbooks I should look into regarding the nyquist-criterion in higher dimensions. For example, this would be relevant if there ...
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25 views

How can I make the mean of samples be approximately equal to the mean of actual continuous signal?

Suppose there is signal $f(t)$ that is continuous and periodic. It is known that this $f$ is $T$-periodic. (but it's not necessarily a single cosine $f(t)$.( I'd like to make the mean of samples be ...
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36 views

What's the sampling frequency when synthetically generating data?

Say I am using matlab's random number generator to get an array of random numbers, which I will then, for testing purposes, find the spectral density etc. For that purpose I need to know the sampling ...
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133 views

Why is telephone audio sampled at 8 kHz?

When did we decide to sample telephone at $8$ kHz? Has this always been the case? Why did we do that? Is it because higher bit rates can't be transferred as quick? And do these reasons still count? ...
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216 views

A question about the sampling theorem

Let's say I have a signal, containing frequencies up to $30$ kHZ. I am sampling this signal at $40$ kHz with infinite bit depth (just for theory). Will I be able to recover exactly all the ...
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41 views

Playing back an audio file at an arbitrary rate with upsampling and downsampling

Background: My overall goal is to create an audio file player which can playback an audio file at an arbitrary rate. The rate can change continuously as the file plays. This means upsampling to ...
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30 views

Can sample aliasing of strictly white noise lead to random walk (drift) in the sampled signal?

Aliasing of tones higher than the Nyquist frequency, and where the tone may have some degree of nonlinear distortion can appear as low frequency 'drift' or even near static bias in the sampled signal. ...
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45 views

just getting started in Signal Processing - easy question

I am reading Cycle Analytics for Traders by John Ehlers and need help. in the first section "Transfer Response" he refers to: so if I had $4$ prices say $8+8+8+8$ then average would be $8$ and ...
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27 views

Image warping with subpixel accuracy

I am trying to test the sub-pixel accuracy of an optical flow method and need to generate some synthetic data to do so. I start with an image $I_0$, which is a Perlin noise image and a set of ...
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1answer
56 views

Oversampling and Aliasing

I am really confused about oversampling and upsampling. I know that upsampling means stretching our signal in time domain by a factor of K, then interpolating some values or using just zeros. As I ...
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23 views

Noise from quantization and sampling frequency

How to estimate if noise of sampled sound signal can be heard? I mean the noise that appear when an analog wave is sampled. Similarly if I use 16bits, 24 bits, and 32 bits resolution, how to ...
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31 views

What's the use case and explanation of frequency-domain subsampling?

In my solution to a certain problem I use subsampling in the frequency domain. Amazingly, it produces good results. Is it really that awkward to see subsampling in frequency domain? What the ...
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32 views

How does sampling and subsequent resampling affect aliased harmonics?

If I sample a signal with a harmonic higher than half my sample frequency I can predict the aliased frequency easily as $$|F_h-kF_s|$$ But what if after sampling the signal, I re-sample at a lower ...
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25 views

detecting position of lost samples

I have a pulse signal from which I sample N times of level changes (e.g. high->low). At undefined times the pulses in the original signal are completely missing. This leads to wrong number of ...
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9 views

Is a complementary filter usable with irregular readings?

I'm experimenting with a complementary filter for sensor fusion (the usual acc/gyro/mag). I've read whatever I could google, but two things are not very clear yet: (1) can a complementary filter be ...
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124 views

What is the sampling rate in this case?

A signal $x=\sin(\pi t/4)$ sampled at every $t=1$ sec. so $T=1$ sec Sampled signal is then $x=\sin(\pi n/4)$, What is the sampling rate in this case?, And according to Nyquist sampling rate what ...
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27 views

adequate sampling frequency in measuring acoustic emission

I am measuring acoustic emission signals. The ae frequency range is 20000 to 1000000Hz. The sampling frequency that i,set was 100000 Samples per second. I must be able to detect a maximum of 50000Hz ...
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130 views

What is meant by *sampling* in terms of the *sampling theorem*?

Let $y:\left(-\frac T2,\frac T2\right)\to\mathbb{C}$ be a square integrable function. The Fourier coefficients of $y$ are $$\underline{Y}(k):=\frac ...
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1answer
50 views

Processing 47-53 MHz signal sampled at 96000 Hz

I am fairly new to the topic of DSP and FFT and I have hit a mental block. For a project, I am trying to pick out frequency's with amplitude peaks in a 47-53 MHz signal. This signal is being put ...
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80 views

Sampling theorem and signals explained to a mathematician

Let $f:\left(-\frac T2,\frac T2\right)\to\mathbb{R}$ for some $T>0$. The Fourier coefficients of $f$ are $$\left\{\begin{matrix}a_0&=&\displaystyle\frac ...
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48 views

filter out an expected but not regular signal

I am stuck with a case where I need to get rid of a portion of sinusoidal signal that suddenly appears in my main signal (sine wave). my total signal will look like: $ s(n) = \begin{cases} ...
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29 views

Sampling rate effect on quantizer SNR

I am currently reading the 'Coding' chapter on Rabiner & Schafer's Book on speech processing. In one of its exercises, the reader is given a simple A/D converter using 16-bit uniform ...
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1answer
132 views

What is the difference between cubic interpolation and cubic “Spline” interpolation?. How to use it for upsampling purpose?

After considering a couple of advices and suggestions for upsampling techniques here, I finally converged to use the cubic interpolation technique to estimate the voltage values corresponding to ...
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2answers
52 views

How to choose sampling rate for non-band limited signal given as an expression?

I have a signal given as an expression $x(t)$. In frequency domain most of the information is around 0 and higher frequencies progressively get smaller and smaller compared to DC component. I was ...
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42 views

Output of a band pass filter

Signal x(t) = | cos(2πft)|, f != 0 is the input of an ideal band-pass filter with bandwidth B = 3f/2. How can i Find the ...
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1answer
42 views

Claim: Given sampling time T, the hold operator is approximated at low frequency by a time delay of T/2

Can someone verify this statement? The hold operator is assumed to be a zero order hold Then the laplace transform of this hold operator has a well known form $(1-e^{-sT})/s$ Let w approach 0, we ...
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64 views

Signal Sampling

I am new in this field (junior year) and I have a question may a little lazy for the majority of the forum. I have a speech signal $ x(t)=0.4\cos(100πt)+0.3\cos(1800πt)+0.2\cos(980πt)$ and I know ...
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41 views

When sampling theory condition fails, what should I do?

I met with a problem: if I sample audio data at 11kHz (yes, that is slow!) for 10 seconds and apply a Fourier Transform to the data, at what frequency will a 15 kHz tone appear? So the original ...
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1answer
29 views

How does sampling a frequency result in a duplicated spectrum?

This is probably a simple question, but I have a hard time understanding how c. converts to d. in the following picture. Further reading as an answer is acceptable. After all, I am only asking this ...
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2answers
96 views

Best Approach on How To Sample and Process

I'm looking for some advice, I am hoping one of the many forum experts could help me with some advice on the sampling and processing of signals. I am using an STM32F4 processor with 12 bit ADC and DSP ...
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1answer
45 views

Sampling orthogonal signals

Suppose I have two signals $f,g$ which are orthogonal in the sense of the usual inner product on $\mathbb R^d$. Then if I'm not mistaken these signals have disjoint spectral support, i.e their fourier ...
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119 views

Shouldn't the Sampling Theorem imply that there should be no information loss at all after a signal is processed?

I am very, very new to signal processing (only started a few days ago) so please bear with me because I may be missing the big picture. Consider an arbitrary signal $x(t)$ with varying frequency to ...
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1answer
48 views

retrieve phase of an extrapolated periodic 1D signal

I have a periodic signal on a given grid, say (in matlab format): ...
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27 views

Compute the impulse response from analog frequency response sampling

I want to compute the impulse response of a linear analog system. I have measured the frequency response of this system, say $H(f)$, at many frequency bins(fixed step size), and obtain a vector ...
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17 views

Simple stats and sampling question

Please correct me if I am wrong here... If I am sampling a signal whose value is constant I measure N times for N samples. I then get a mean and standard deviation (SD). I obtain a relative standard ...
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1answer
22 views

Sampling: how to determine a “good” sampling rate based on a given filter

I assume that the sampling rate is w_s = 2w_max if we have an ideal low-pass filter that nulls frequencies whose absolute value is higher than that of w_max. Therefore, that the only reason for ...
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1answer
35 views

What happens to the fourier transform of sample result of $30kHz$ sinusoidal signal when sampled with sample frequency $44.1KHz$?

As the title says,w hat happens to the fourier transform of the sample output of $30KHz$ when sampled with sample frequency $44.1KHz$? I do not get how alias can appear, because fourier transform of ...
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15 views

What is the best way to construct time-domain data to minimize harmonics?

I'm attempting to use a Fourier transform in order to detect the frequency of particular types of discrete events. The events themselves are by their nature completely discrete with no duration. ...
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39 views

How to choose sampling rate?

I am working on a FMCW radar and I want to sample the I/Q signals from the 2 receiving antenna (total 4 channels) simultaneoulsy and send the digital data to computer to extract range and velocity ...
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1answer
39 views

DFT independent variable as fraction of sampling rate

When the frequency domain's independent variable is labeled as a fraction of the sampling rate, the values along the horizontal axis always run between $0$ and $0.5$, since discrete data can only ...
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1answer
90 views

why Sampling with higher than nyquist frequency is causing aliasing?

fm=20000 and I am sampling following signal at 65000 Hz: ...
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76 views

Processing IQ signals [closed]

Signal Characteristics: The IF (I/Q) signal consists of a DC component and an AC component. DC Component: 2.52V; AC Component: 1.72 – 2.04 V (V P-P); BW: 20Hz - 500kHz; Power: 20dB Requirement: Now ...
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180 views

Is digital up and down sampling linear/causal/time-invariant?

So I am trying to determine whether the process of up sampling (zero padding) and downsampling are linear, causal and/or time-invariant. Based on some resources I found online, I am under the ...
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1answer
55 views

Codec Output has “Wavy” Amplitude on Chirp Input

I am sending a chirp that sweeps form 20Hz to 500Hz to an audio codec, CS42L52, connected to an MCU, STM32F405, and I am receiving a "wavy" amplitude output. There is no processing on the MCU, I pass ...