Nyquist????

Started by krish_dsp in comp.dsp9 years ago 41 replies

Hi everyone, What is the dirrerence between nyquist frequency, nyquist rate and nyquist bandwidth? I am sure that they dont point to the same...

Hi everyone, What is the dirrerence between nyquist frequency, nyquist rate and nyquist bandwidth? I am sure that they dont point to the same concept. I know what is a nyquist frequency. But I am not able to understand the concept of the other two. I came across these terms while learning about pulse shaping filters (raised cosine filters). I tried to understand, but still I am not able to compl...


Implications of Nyquist? ?????

Started by Richard Owlett in comp.dsp8 years ago 24 replies

_TYPICALLY_ when looking to satisfy "Nyquist criterion" one looks to sample a waveform at > = a particular frequency. I've gut feeling that...

_TYPICALLY_ when looking to satisfy "Nyquist criterion" one looks to sample a waveform at > = a particular frequency. I've gut feeling that Nyquist implies more. I suspect it's more about information transfer rate. What question should I be asking. Signed ADMITTED *STUPIDENT*


Nyquist Condition question.

Started by A.E lover in comp.dsp10 years ago 1 reply

Hi all, (1) I know the famous Nyquist Condition, f(t) with bandwidth B is sampled without aliasing if Fs> 2B. Today I read another...

Hi all, (1) I know the famous Nyquist Condition, f(t) with bandwidth B is sampled without aliasing if Fs> 2B. Today I read another thing called Nyquist Condition which says: for a continuous time signal x(t), take x(t) convolute with itself and then sample the obtained signal at Fs, if the sampled signal =delta[n], then Fs satisfies the Nyquist condition i.e: g(t)= x(t) (*) x


Nyquist and Shannon

Started by RichD in comp.dsp1 year ago 10 replies

Probly been asked many times, but - Why is the sampling theorem called Shannon-Nyquist? Nyquist published his paper in 1924, what was...

Probly been asked many times, but - Why is the sampling theorem called Shannon-Nyquist? Nyquist published his paper in 1924, what was Shannon's contribution? Where was the original's deficiency? -- Rich


What Nyquist Didn't Say

Started by Tim Wescott in comp.dsp11 years ago 62 replies

I've seen a lot of posts over the last year or so that indicate a lack of understanding of the implications of the Nyquist theory, and just...

I've seen a lot of posts over the last year or so that indicate a lack of understanding of the implications of the Nyquist theory, and just where the Nyquist rate fits into the design of sampled systems. So I decided to write a short little article to make it all clear. It's a little longer than 'short', and it took me way longer than I thought it would, but at least it's done and hope...


Does anyone have any reference to sampling distortion?

Started by Steve in comp.dsp14 years ago 4 replies

To all you DSP mavens out there. I am looking for some references to distortions introduced by sampling = errors, especially sampling close...

To all you DSP mavens out there. I am looking for some references to distortions introduced by sampling = errors, especially sampling close to the Nyquist criterion. In all the = literature I have seen, reconstruction of a waveform is guaranteed if the sampling = meets the Nyquist criterion, that is sample rate > 2F. =20 There are lots of cases where the Nyquist criterion doesn't seem


Nyquist

Started by Steve Pope in comp.dsp1 year ago 16 replies

I see where the Kentucky Derby winner is "Nyquist". Surely there is a story behind this... S.

I see where the Kentucky Derby winner is "Nyquist". Surely there is a story behind this... S.


is normalizing FFT magn spectrum different for Nyquist-frequency's bin?

Started by all4dsp in comp.dsp7 years ago 19 replies

Hi Experts, Let's say I compute the FFT magnitude spectrum of a variable X(n) in Matlab, where X(n) has indices n running from 1 to N. The...

Hi Experts, Let's say I compute the FFT magnitude spectrum of a variable X(n) in Matlab, where X(n) has indices n running from 1 to N. The magnitude spectrum is plotted for indices n = 2 (ignoring DC index n=1 for now) to n = N/2 + 1 (e.g. the Nyquist frequency bin). To get the normalization correct, should the Nyquist-frequency bin's magnitude be cut in half, because the Nyquist bin is n...


nyquist sampling rate

Started by Anonymous in comp.dsp8 years ago 12 replies

hi all. i have a signal of bandwidth 2 MHz on a carrier of 5 MHz. That means the Nyquist sampling rate is (5+2/2)*2 = 12 MHz. But I have heard...

hi all. i have a signal of bandwidth 2 MHz on a carrier of 5 MHz. That means the Nyquist sampling rate is (5+2/2)*2 = 12 MHz. But I have heard that it is not a good idea to sample on or near nyquist rate because of the sinx/x roll of charactersistics of ADC. Please guide should i oversample it a little such as 16 or 20 MHz. I am working on a communication system so the system is performance ...


Nyquist theorem and Sampling rate of signals (Newbie)

Started by Deamon in comp.dsp7 years ago 15 replies

Please I am a complete newbie in Signal analysis and modelling and I am quite confused about the use of Nyquist theorem in sampling .Does this...

Please I am a complete newbie in Signal analysis and modelling and I am quite confused about the use of Nyquist theorem in sampling .Does this Nyquist criterion affect the rate at which data is transferred that is the data rate ? I have read the wikiopedia saying that I must sample at twice the bandwidth to be able to recontruct a signal perfectly But I don't understand the concept . If ...


Nyquist rate for sampling complex-valued data?

Started by kiki in comp.dsp13 years ago 14 replies

I (vaguely) heard that sampling complex-valued data does not abide by the Nyquist rate criteria, i.e., the sampling rate fs can go lower than...

I (vaguely) heard that sampling complex-valued data does not abide by the Nyquist rate criteria, i.e., the sampling rate fs can go lower than Nyquist rate and it still can avoid aliasing and reconstruct perfectly... Is that true? Any theory behind it? Thanks a lot


Nyquist For Chirps

Started by John Harkes in comp.dsp5 years ago 19 replies

So when sampling a signal Nyquist (assuming first Nyquist zone) says you get half your clock rate. I have always followed the rule that you get...

So when sampling a signal Nyquist (assuming first Nyquist zone) says you get half your clock rate. I have always followed the rule that you get closer to 40% of your clock rate. My question is what about chirps or swept FM. Lets assume you chirp from 100MHz to 500MHz then I would want to run my A/D at 1.25GHz to swallow this signal. If I chirp from 100MHz to 500MHz in 100ns that


Nyquist Pulse

Started by Aitezaz in comp.dsp8 years ago 4 replies

Nyquist pulse criteria states that the summation of the spectrum of pulse shapes should be flat. But if we see in time domain there are many...

Nyquist pulse criteria states that the summation of the spectrum of pulse shapes should be flat. But if we see in time domain there are many pulse shapes that satisfy the nyquist criteria and they dont have a spectrum that's summation is flat. For example, triangular function f = { t + T for -T


Information request about sub-Nyquist and irregular sampling

Started by vanu in comp.dsp8 years ago 6 replies

Hi, I am new to signal processing and have very simple question. Where can I find a brief explanation about sub-Nyquist and irregular sampling....

Hi, I am new to signal processing and have very simple question. Where can I find a brief explanation about sub-Nyquist and irregular sampling. I searched the web by almost all possible keywords, but what I found is not so useful. It would be very nice if you give me some book titles. Thanks in advance!


Help w/ PSK, Nyquist filtering etc

Started by Shimbun in comp.dsp12 years ago 7 replies

Hi, Some help with explaining some digital communications stuff would be much appreciated. This is not really my field and I'm having a hard...

Hi, Some help with explaining some digital communications stuff would be much appreciated. This is not really my field and I'm having a hard time understanding some concepts that are probably pretty basic. It's not really DSP related as such; it is more fundamental. I think I understand the need for Nyquist filtering to reduce bandwidth while maintaining the ability to unambigously det...


Nyquist Didn't Say That

Started by Tim Wescott in comp.dsp11 years ago 187 replies

Kinda off topic -- A month or two ago there was a spate of postings on these groups displaying a profound misunderstanding of how to apply...

Kinda off topic -- A month or two ago there was a spate of postings on these groups displaying a profound misunderstanding of how to apply Nyquist's theorem to problems of setting sampling or designing anti-alias filters. I helped folks out as much as I could, but it really demands an article, which I am currently working on. The misconceptions that I noticed pretty much boiled down...


Nyquist Sampling

Started by RF in comp.dsp10 years ago 4 replies

I'd like to ask a couple very basic questions. Being hands-on rather than mathematically-focused I'm trying to visualize sampling in a project...

I'd like to ask a couple very basic questions. Being hands-on rather than mathematically-focused I'm trying to visualize sampling in a project I'm planning to start. 1. By sampling say a 3.1 kHz band-limited voice channel at the Nyquist rate am I guaranteed to capture *all* the information in the channel? Is nothing lost (ignoring ADC resolution)? More to the point: To know what the ...


Johnson Nyquist Noise

Started by Clay in comp.dsp11 years ago 12 replies

Hello All, I had a recent situation where I needed to write a paper explaining the why's and wherefores of Johnson noise. So if you are...

Hello All, I had a recent situation where I needed to write a paper explaining the why's and wherefores of Johnson noise. So if you are interested, the following link will take you to my paper. http://www.claysturner.com/dsp/Johnson-Nyquist%20Noise.pdf Any and all comments welcome. Thanks, Clay


I wonder if there is a spatial Nyquist sampling theory?

Started by walala in comp.dsp13 years ago 10 replies

Is there a Nyquist sampling theory for spatial dimensions? Suppose point A to point B is about 1 mile, how many sensors I should place to get...

Is there a Nyquist sampling theory for spatial dimensions? Suppose point A to point B is about 1 mile, how many sensors I should place to get a fair estimation of the property of the whole range?


Low pass filter at half Nyquist

Started by VelociChicken in comp.dsp9 years ago 32 replies

Hello, I'm currently using an FFT to zereo out all the frequences above half Nyquist for my application. It makes perfect cutoff, but I have to...

Hello, I'm currently using an FFT to zereo out all the frequences above half Nyquist for my application. It makes perfect cutoff, but I have to use buffers and the old overlap/add to remove clicks. My question to you good folks - is there a clever 'trick' to cut frequencies off above this specific (SR / 4) point using time domain techniques? Or a more efficient frequency domain method? ...