Tagged Questions

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

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2
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1answer
62 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 ...
0
votes
1answer
28 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 ...
0
votes
0answers
27 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 ...
0
votes
1answer
21 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 ...
0
votes
4answers
51 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 ...
0
votes
1answer
72 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 ...
-1
votes
1answer
42 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 ...
0
votes
1answer
32 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 ...
2
votes
2answers
63 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 ...
0
votes
1answer
34 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 ...
0
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0answers
22 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 ...
1
vote
1answer
50 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 ...
0
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0answers
22 views

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 ...
1
vote
1answer
79 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 ...
-1
votes
1answer
62 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 ...
0
votes
1answer
50 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?
2
votes
1answer
78 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 ...
0
votes
0answers
12 views

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 ...
8
votes
3answers
1k views

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?
1
vote
0answers
16 views

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 ...
0
votes
3answers
74 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 ...
2
votes
2answers
140 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 ...
0
votes
1answer
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 ...
0
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0answers
70 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 ...
0
votes
1answer
60 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 ...
0
votes
1answer
18 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
0
votes
1answer
27 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
0
votes
1answer
40 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 ...
0
votes
2answers
64 views

Sampling fast sinusoidal signal with low sampling rate

I have sampling problem that I am trying to solve analytically I have sampling frequency, let say 1kHz. I have number of target frequencies, let say 10kHz,100kHz,1MHz For each target frequency I ...
1
vote
1answer
55 views

What does it mean for audio to be 'sped up'? How can I undo it?

I very simply have a .wav audio file, but there is a note with it that says "This audio has been sped up by 10x". I am wondering, what does it mean exactly from a signal processing perspective for an ...
1
vote
1answer
106 views

Implementations of Low-Pass Filter

I should say which of the filters from the following image implements an ideal low-pass filter with cutoff frequency $\frac{\pi}{4}$. In the picture, Sa is a zero insertion filter, which inserts a ...
3
votes
1answer
52 views

oversampled coefficient for existing exponential smoothing

Say I have an exponential smoothing for certain $\Delta t$, $t_{i+1} = t_i + \Delta t$. In this sampling, I choose a particular $\alpha$ to filter signal $z_i$ like $$ v_1 = z_0 \\ v_{i+1} = ...
4
votes
1answer
167 views

Why can't DFT be used when samples are not equally spaced in time?

I found the following comment here The DTFT can be used when the samples are not equally spaced in time, the DFT cannot My initial thought was that this had to do with periodicity of the basis ...
-1
votes
1answer
38 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.
1
vote
1answer
42 views

Is phase and amplitude information necessarily lost when undersampling?

Is phase and amplitude information necessarily lost when undersampling if you have a constant periodic single frequency sinusoidal? My second question is: How can one determine the undersampling ...
0
votes
1answer
66 views

Ideal Reconstruction of Upsampled Signal

Problem: The signal $cos(2\pi14100t)$ is sampled at $F_s = 400 Hz$. It is then upsampled with a factor 3 and then reconstructed ideally with a new frequency $F = 500 Hz$. I now want to find the new ...
1
vote
2answers
139 views

FFT of Square Wave and Sin Wave

When we have FFT of Square wave of a pure real signal with high frequency(close to f(max), less than half of sampling frequency) we see only 2 symmetric high peaks but when we decrease the frequency ...
1
vote
1answer
72 views

Calculate Max Number Of Harmonics for given Sample Rate?

How do I calculate the maximum number of harmonics a complex wave can have based on the sample rate? Say I Have a 20hz fundamental and a sampling rate of 44100 hz. My instinct is to take 44100/2 = ...
2
votes
1answer
164 views

Sampling frequency of modulated signal

A very naive question... A signal with bandwidth of 20 MHz is modulated using a carrier of 1 GHz. What will be the sampling frequency? I was asked this question during an interview. I answered 2 GHz ...
1
vote
1answer
118 views

Does audio upsampling create noise/artifacts or degrade the signal?

I've read that upsampling performed in digital music playback can color the sound, produce artifacts, etc. For example, an audio file ripped from a CD might be 44.1Khz/16-bit, and then upconverted to ...
1
vote
0answers
34 views

Calculate the intersample peak of a periodic sequence?

Similar to Calculating the PDF of a waveform from its samples, but for periodic sampled signals, and I just want the peak. Is there a way to calculate the highest inter-sample peak of the ...
1
vote
2answers
128 views

Computing shifted signal without first reconstructing

Looking for a solution to the following problem: A signal $x(t)$ is band limited to $B$ Hz, and sampled above the Nyquist rate, with corresponding $f_s = 1/T$. If the sampled signal is given ...
0
votes
1answer
50 views

How to calculate BW ofdm?

HI I have these specification for an OFDM program I was wondering, what is the bandwidth and the sampling frequency? I'm not a student of Digital signal processing, hence I am so confused. ...
1
vote
2answers
120 views

Nonuniform sampling band-limited gaussian white noise

I'd like to sample band-limited Gaussian white noise non-uniformly. One way to approximate this would be to filter Gaussian white noise with a lower cutoff frequency and non-uniformly pick samples ...
0
votes
1answer
39 views

correcting delay between two samples

I'm sampling two signals with fundamental frequency of 50 Hz. I want to sample them at the same instant, but there's a delay between the first and the second conversion. I don't keep the previous ...
1
vote
1answer
56 views

What does “two signals aliasing to each other” mean?

So I just read something that two signals are aliasing to each other. I know what a single signal is being aliased - that is when sampling rate is not higher than or equal to the Nyquist rate. But I ...
0
votes
0answers
26 views

Matlab:Sampling Curve into Frames and Plotting

I have a Output Curve of following characteristics http://i.imgur.com/hABfsiC.jpg Following is the data which represents the output curve cited above ...
1
vote
1answer
27 views

Why do we observe band when recording CRT monitors or Flouroscent lamp via video recorder?

I understand that this has something to do with difference between refresh rate of monitor (or line frequency used by the ballast in case of Fluoroscent lamp) and frame capture rate of video recorder. ...
3
votes
0answers
50 views

Interpolating on the borders of differently-resolved images

I'm creating a three-dimensional model of the earth based on SRTM height data. The data set is pretty huge, so only a small fraction of the data is available at any given time. The height data is ...
0
votes
1answer
162 views

Java amplitude processing

I have some code that collects amplitudes from a complex sound like a song. I now want to plot a graph of amplitude vs time, for the graph plotting I use JavaFX. However I get about 9 million ...