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

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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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56 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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36 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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19 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
60 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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42 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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104 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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40 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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22 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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20 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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34 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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12 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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31 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
33 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
80 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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57 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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1answer
59 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
40 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 ...
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35 views

What is a correct way to downsample an impulse train

So I have a signal which is caused by an impulse train. I can determine the impulse train with 500hz but sample my output signal with only 10hz. Then I want to calculate an impulse response function. ...
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1answer
80 views

FFT on Hamming Window Function [duplicate]

I want to apply Hamming window function the Audio sample then find out its fft.. ...
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1answer
62 views

Extending a waveform

Apologies if this makes no sense or seems rather simple, I'm a Matlab newbie. Basically, I've got a .wav audio waveform which I am resampling to various different frequencies and then trimming the ...
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1answer
130 views

Sound quality with really high sampling rate, but really low bit depth with dithering?

This question is probably more for fun and theory, but how will the sound quality be, if you create a sound with really high sampling rate (like 192kHz) and really low bit depth (e.g. 3bit)? Can you ...
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50 views

Given two waves, 441 Hz and 700 Hz, how many samples long is each wave's period if the sample-rate is 48 kHz?

The title says it all. I have two waves, Master and Slave. Master is at 441 Hz and Slave at 700 Hz. The sample-rate is 48 kHz. I want to know how to calculate the period of each wave in terms of ...
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42 views

What are the frequency components of a sampled signal after low-pass filtering?

A continuous signal $x_a(t)$ is a linear combination of sinusoids of frequency 250 Hz, 450 Hz, 1 kHz, 2.75 kHz and 4.05 kHz. The signal $x_a(t)$ is sampled at $f_s=$1.5 kHz, and the resulting digital ...
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36 views

Effect of Sampling frequency on RMS estimation

I have a simple, but interesting question for you. I have to compute the RMS (root mean square or standard deviation) value of a time signal which represents in my case a velocity mesasurement over ...
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85 views

up sample and down sample

Let's say that I have a sampled signal x[n], it is being, in this exact order, up sampled by 2, down sampled by4, up sampled by 4 and down sampled by 2 to produce y[n]. It seems to me that it should ...
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89 views

Strange Results from Biquad Peaking EQ Filter

I have a signal that I am filtering on an MCU (STM32F405) that I get from a codec (CS42L52). It is being sampled at a sampling frequency of 48kHz (actually between 48400 and 48600). I have a ping ...
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47 views

Can someone please help me out with audio, sampling frequency question

I really having a hard time to tackle the following question. It is asked to load a ".mat" file using load file.mat. And the result is two variables: Fs varaible ...
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1answer
36 views

Implementing discrete time systems

Discrete time systems work on sampled continuous time signals. We need samples only at discrete time to be fed as input to a discrete time system. Does this mean discrete time systems are clocked so ...
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67 views

Can the order of filtering and downsampling be exchanged?

Say for example, I have a signal with maximum frequency at 600Hz, and I originally oversampled it at 2000Hz. Afterwards I was only interested in frequency less than 500Hz. I guess I could first filter ...
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36 views

Basic sampling problem - could use some advice

I have a problem in my DSP class that I could use some advice with. An analog signal of length 2.5s is sampled with a Nyquist frequency and the sampled sequence has 5001 values. What is the highest ...
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24 views

Can uneven sampled points generate valid PSD and spectrogram?

My recording device samples signal at 100 Hz. At each sampling point, it generates 512 values (I assume due to non-ideal impulse in practice, so each impulse is actually a window with certain width ...
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54 views

Sampling distance

In paper: A. Vlad, A. Luca, and M. Frunzete, "Computational measurements of the transient time and of the sampling distance that enables statistical independence in the logistic map," in ...
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detecting frequency bursts in GSM using ALE, mystery peaks

http://ieeexplore.ieee.org/xpls/icp.jsp?arnumber=1404796 I've implemented the algorithm in the mentioned paper. From the error function, I can clearly see the filter converging to the FCH (Frequency ...
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161 views

Sampling rate in Wifi 802.11 -> 20 MHz enough with a BW of 20 MHz?

In a Wifi 802.11n context, I'm looking to find the sampling rate to perform some processing on the signal and I've something I cannot understand : in the book Next Generation Wireless LAN's: 802.11n ...
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80 views

FFT of signals with different sampling frequency

I am trying to combine two sets of data together, each of them having different sampling rates. For example if I sampled a 100 Hz sin wave at 1KSPS, and another 150Hz sin wave at 1.5KSPS, would it be ...
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58 views

relationship between energy and sampling rate

Excuse my silly question, but i really want to know does changing the sampling rate affects the energy (bandwidth) of a signal? therefore improves cross correlation output?
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102 views

How does the number of frequency-domain sampling points influence the outcome of an inverse FFT?

Given some frequency-domain representation of an impulse response. How does the number of frequency-domain sampling points influence the outcome of an inverse FFT, if I keep the sampling frequency ...
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Gaussian kernel standard deviation and spacing

Suppose I know the normalized gaussian weights for a kernel of standard deviation 1.0 evaluated in the sample positions $O = \{-2, -1, 0, 1, 2\}$. Let's call these G. I know that the same values G ...
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Why do we choose 44.1 kHz as recording sampling rate

People's ear can hear sound whose frequencies range from 20 Hz to 20 kHz. Based on the Nyquist theorem, recording rate should be at least 40 kHz, is it the reason choosing 44.1 kHz?
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Anti-aliasing requirements for a Muxed Sigma-Delta Converter

It seems to be reasonably well accepted that Sigma-Delta ADCs have much looser requirements for the anti-aliasing filter due to both the noise shaping and high modulation frequency. However, it seems ...
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86 views

Decimate/downsample a signal from 1920.93Hz to 1920Hz. Possible? [duplicate]

I've just learned that the A/D converter I am using is not sampling at my desired sampling rate. I request 20 seconds of data at 1920Hz and I receive 38400 points of data that were actually sampled ...
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183 views

Using Goertzel Algorithm in under-sampling

I plan to calculate a signal's phase using Goertzel Algorithm. I have 2 signals coming to microcontroller's ADC. Need to measure the phase difference between them. Signals are 15MHz sinusoids. Sample ...
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33 views

Sample vs. sample values

Is there any difference between the terms sample and sample value in DSP? In statistics, those are very different concepts: a sample is a subset of a population: it is a set of random variables. A ...
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84 views

Recording square waves at sample frequency

For a project I am working on, I need to incorporate GPS data into an audio file. As things currently are, the easiest way for me is to record the audio in a multi-channel .wav file, and add the GPS ...
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80 views

How may samples per symbol in ieee 802.11 g

I am doing a baseband simulation for IEEE 802.11 g. The standard uses 64 IFFT length ($3.2 \mu s$) and 20 Msamples per second. This result in one sample per symbol. I am wondering what the structure ...
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20 views

Vector of random numbers with fixed sampling rate

How to create a vector of random numbers(in Matlab), when each value is [0,1] . And the sampling rate should be fixed ? thanks
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28 views

Identification of sampling frequency

I have the following vector: %create vector of sampling t=0:pi/100:2*pi; x=sin(t); What is the sampling frequency (of this vector) ? Thanks
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43 views

Is there a way to break an analog sound signal up and send it through two radio chips at double the data rate of one?

Here is a radio chip for audio that sends at a CD-level data rate. Could you sample an analog signal (for instance from a guitar pick-up or microphone) in such a way that you could transmit using two ...