Questions tagged [sampling]

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

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194 views

Can somebody help me solve this signal accumulation problem?

Investigation of the method of suppression of random noise by coherent signal accumulation Purpose - to identify opportunities for the coherent accumulation for cases of stationary and quasi-...
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274 views

Direct IQ sampling symbol transition problem

In a direct sampling RF front-end, we can get real samples. But when we sample the signal with two ADC with a sampling delay $ \frac{4n+1}{4fc}$ where $n$ can be $0,1,2 \dots$ Then we have In phase(I) ...
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Trying to understand whether digital signals help in better bandwidth utilisation or not

Suppose x(t) is a continuous-time signal and x(n) is a discrete time signal obtained by sampling the signal x(t) at a Nyquest sampling frequency Fs. The signal x(t) requires a bandwidth of B1 Hz for ...
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4answers
309 views

Nyquist Theorem - Why unique frequencies upto Fs/2 and not Fs? f+Fs is start of Aliasing

If any frequency, f, displays an alias at f + Fs, This shows that unique frequencies have a range of Fs. Why does Nyquist theorem say that actually there is only half of this with unique frequencies ...
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3answers
5k views

Calculating maximum signal frequency knowing its sampling rate?

I was curious as to how I could calculate the maximum frequency of a signal knowing only its sampling rate (for example 125 nanoseconds). Does the sampling theorem have anything to do with it (...
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2answers
187 views

Derivation of Nyquist Frequency and Sampling Theorem [closed]

I have been looking through different sites and questions over the internet about Sampling theory, but couldn’t find the clear definition of how nyquist frequency condition is derived? It would be ...
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1answer
57 views

If a person at rest has an average heart rate between 60 and 100 beats per minute, how manysamples should you plot to obtain 5 beats in the signal?

If a person at rest has an average heart rate between 60 and 100 beats per minute, how many samples should you plot to obtain 5 beats in the signal?
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2answers
224 views

Plot the spectrum and n-point DFT

$x_a(t) = \cos(2\pi f_a t)$ was sampled with sampling period $T_s$. Plot the { spectrum | $N$-point DFT } of $x[n]$ ($f_a$, $T_s$ or $f_s$ given, $N$ given - whole number of periods or not). Anyone ...
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1answer
43 views

From where this Laplace transform for tracking error came?

System for estimating the tracking error in an A-D converter. Let $e_i(t)$ be ramp function with slope $e_i'$ and assume that the sampling switch is closed at $t = 0$, at which time $e_i = e_0$...
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1answer
143 views

What is the best approach for studying the information within frequencies of an unknown signal

If we have a signal and we do not know anything about this signal. We do not know which frequencies contain specific information, and which frequencies does not contain information. Which is the ...
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1answer
58 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
372 views

AM demodulation from a real RF signal

I'm capturing an RF signal transmitted at 433.8MHz, with a bandwidth of about 50KHz. My goal is to be able to save it as a .wav file. I'm using an RTL-SDR dongle and a software named HDSDR, where I ...
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1answer
105 views

On number of samples needed

Suppose we get $m+1$-bit signed noise samples $n_i$ with magnitude of noise as high as $m$ bits. Does averaging say $m\log m$ samples suffice to get average of $n_i$ to magnitude within few LSBs? ...
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1answer
363 views

Accuracy of sampling rate

I have data corresponding to 300 seconds. Sampling rate is 500Hz. I should have 500*300 = 150000 samples. But due to hardware error, I am receiving a few extra samples. What is the optimal way of ...
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1answer
180 views

Closed-form expression for Whittaker-Shannon interpolation for non-bandlimited signals

For a bandlimited signal $x(t)$ that is reconstructed after Nyquist-sampling at intervals $T$, $$x(t) = \sum_{k=-\infty}^{\infty} {x[k]\textrm{sinc}\left(\frac{t-kT}{T}\right)}$$ where $x[k]$ = $x(...
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1answer
125 views

Nyquist Rate Determination

If the Nyquist rate for xa (t) is Ωs, what is the Nyquist rate for xa(2t)? Will it be the same, increase 2 folds or decrease 2 folds?
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1answer
22 views

What happens when the frequencies of the signal does not lie within the reconstruction filter passband?

Assume we have an analog signal that has frequency components between 40Hz and 50Hz and 0 otherwise. If we sampled this signal with 100Hz sampling frequency then passed to DAC with the same sampling ...
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1answer
1k 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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1answer
652 views

how to sample sine wave to 4 points dft output

sinusoid x(t)=1+sin(2*pi *500) sampling rate :1000 samples/s Can I have 4 points DFT output with the above data.
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1answer
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Aliasing after downsampling [duplicate]

Let me start with time domain representation of the original signal \begin{equation} x_n=\sum_{k=0}^{2N-1}X_ke^{j\frac{2\pi nk}{2N}} \end{equation} where $2N$ is number of time/frequency samples ...
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1answer
44 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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1answer
156 views

What does a fractional frequency (for discrete-time signals) mean/how to interpret it? [closed]

This question has bugged me for a while as it's not addressed in any books I've read. I was wondering how folks from this community interpreted it. Below are my personal notes on the matter (please ...
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34 views

Analogue signal and bandwidth [closed]

An analogue signal has a bandwidth which extends from very low frequencies up to 12 kHz. Using the sampling theorem, what is the minimum sampling rate (numbers of samples per second) required to ...
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1answer
94 views

Can you help me determine what section of digital signal processing discussed in this screenshot?

what kind of filtering is it? How signal/noise ratio in the output mix of the duration of accumulation would look like, knowing Signal/noise ratio=0.1 ,The number of cycles of accumulation of up to ...
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1answer
595 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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5answers
3k views

FIXED POINT conversion Problem (DSP)

Actually after reading the data from ADC is an $Q15$ format (ie. ADC supports 0-3.3v, ADC is an unipolar type). then the $Q15$ data is converted to $q31$ format ($Q31$ value = $q15_{data}$ <<16)....

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