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Sampling with non-equidistant sampling period

Hi, I'm interested in sampling a signal with a non equidistant sampling schema, e.g.: T1, T2, T1, T2, T1, T2, ... It means, sampling at times: t1 = 0 t2 = t1 + T1 t3 = t2 + T2 t4 = t3 + T1 t5 = t4 + T2 etc. - Who knows how to analyse the spectrum of such a data sequence? - What ...

Re: A few queries

You are right, that makes sense. So it seems like this is could be a drawback of sampling faster than necessary (assuming a trade off between sampling rate and sampling time)... ...

Problem in Sampling

Hi , I found one problem in sampling a continuous time signal. The signal frequency is 4000Hz. According to the Shanon's sampling theorem, the sampling frequency should more than or equal to 8000Hz. But, in one telecom applications i found that , the zero resting samples are missi...

Sampling Rate

Hello Everybody This is basic question. Generally we say that sampling frequency should be integer multiple of the (1/T) i.e. 2/T,3/T.... but what is 'sampling rate = 2.5/T'? In my case sampling frequency is Fs=48KHz, Data Rate=4KHz, center freq Fc=12KHz. Help in this respect will be g...

Sampling Problems

I'm writing some material about sampling for the beginner. I want to include a bit about non-ideal sampling. Assuming that sampling is defined as a process that takes on the value of a continuous-time signal at the instant that t = (sample time) * n, the only difficulties that I can attrib...

bandpass sampling

hello friends i need help regarding bandpass sampling i can see that already lot of discussion had taken in this topic and but i am getting confused after reading those discussion i am having a signal of BW =5MHZ and my Fc=60 Mhz i want to sample this signal with Fsamp=16MHZ ,(according to samp...

Delay by Less than a sampling interval

Hi all, Is it possible to delay digital data, by a fraction of the sampling interval. i.e. if fs=1/Ts, where fs is the sampling frequency and Ts the sampling interval. My understanding is that it can be done with interpolation, but that would require a higher clock. Is it possible without using ...

sampling a perfect sinusoid at Nyquist rate?

Let's say you have a perfect sine wave at frequency w. According to Nyquist, in order to be able to recover the sine wave, you need to have a sampling rate of at least 2w. So if you decide to sample at 2w, you end up with 2 samples for each cycle of this sine wave. If you sample at the peaks ...

What is quadrature sampling

Hi all, What is quadrature sampling?It says that sampling frequency be greater than signal BW.Does it not violate Nyquist criterion?What are its applications? Regards. Raghavendra ...

"Quadrature signals : Complex, But not complicated" by Richard Lyons

Hy, I recently read this good article of Richard Lyons but there is something i can not understand. Does someone could help me understand this difficulty ? It it says : "Each A/D converter operates at HALF the sampling rate of standard real-sampling" !!! How does it work ? It seems ...

The sampling frequency in 802.16Rev2/D2

Hi, here I don't understand the definition of the Sampling frequency in 802.16Rev2/D2 It is defined as Fs = floor(n*BW/8000)*8000 where, n=8/7 is the sampling factor. Q1: According to the Nyquist Sampling Theorem, the Fs should be larger than 2 times of BW. But here, Fs is similar t...

Sampling two carriers with the same sampling frequency

Hi, I am using 444 kHz sampling frequency (fs) to sample two different carrier frequencies: f1=108 kHz and f2=111 kHz. When I look at the sampled f2, the waveform seems to be pretty accurately represented. However, for f1 this is not the case. Even thought the frequency of f1 is represented ac...

coherent sampling and I/Q demod

(how) does coherent sampling (used primarily in A/D testing?) differ from I/Q demodulation? Say for instance I'm using I/Q to close a PLL. In this case the 'sine wave' I'm locked to is being sampled at x4 the sine frequency. This would seem to satisfy the coherent sampling requirement that regarding...

Re: 1D discrete wavelet synthesis

Hi, It helps somehow, however this samplewise is still not clear to me. Anyway thanks for the effort in you explanations. I have just a little question if you don't mind though! It concerns the sampling rate in the downsampling process. for instance if a signal's sampling frequency is 1kHz,...

Re: Digital PLL acquisition problem

I have a frequency sampling of 300 kHz Then after de multipler (phase detector) I decimate with a FIR filter to be 10 kHz sampling to the loop filter so the loop filter is at 10 kHz sampling because I have a strange output of this filter when I compute the coefficients for a sampling frequency ...

FFT length and sampling frequency relationship

Hi All, i was going through DSP book by proakis, there i came across the following realted to for which sampling frequency what is the fft lenght to be used like, Sampling Freq FFT Length 8KHz 256 22KHz 512 ...

Regarding sampling.

Dear Group, I have an elementary question. If a sine-wave is sampled such that the samples fall at the times when the value of the wave is zero (meaning at 0 and pi). The sampling frequency thus is twice the frquency of the wave. Is this proper sampling ? How can we reconstruct such a signa...

sampling rate

Hello all, I am reading a matlab example from Simon Haykin's introduction DSP book. In the example, a discrete time signal is describe as x[n] = e^-(n/15) sin(2*pi*n/13 + pi/8) for 0 f=60/13. But this is wrong? Thanks in advance. FD ...

cutoff and sampling frequency

Hai, Basically i am little bit confused with FIR filter cutoff frequency and sampling frequency relation....Both the terms are very much familier to me separately but i dont know how to relate each other?? Few standard sampling frequencies for audio applications are 8,44.1,48,96,192Khz...Fo...

Sinc interpolation

Hi all, I am modelling sampling jitter in matlab using sinc interpolation. The input is a vector of 256 complex data(16QAM symbols). Have introduced jitter in sampling time as t=k/Fs+k*err where Fs is sampling frequency, k is the symbol index, t is the new sampling instant. I have assumed ...

Bandpass signal sampling

Hi, I have a problem. If anyone may help , I would be appreciated. There are signals at 70 MHz IF output of a DDC. and there are equispace signals which should be demodulated. I am trying to find the best sampling frequency for this purpose. I know about the bandpass sampling theorem whi...

How about higher sampling rate in adaptive antenna array

Hi, In smart antenna domain, the sampling rate normally is the same at the symbol rate. In TDMA systems, there are not many sync symbols which can be used as reference signals. In order to accormodate to the convergence of the adaptive algorithm, some longer sync symbol information is required. ...

Beginner Question - Discrete Fourier Series and sampling

Given I have an input sequence [ 1 0 1 0 1 0 1 0 ], the DFS is x[n] = 0.5 + 0.5*exp(j*pi*n). The sampling (Ts) is 100 secs. Am I correct in saying that the spectral coefficient 0.5 at pi is equivalent to saying the DFS has a 0.5 peak every 200 secs? My reasoning is between adjacent x[n] sam...

Changing the sampling rate of an audio signal.

Hello, I want to change the sample rate of an audio signal. Where can I find some information about it? Some mathematical model and some source code would be perfect. What I want to do is: I have a device that can play audio signal with the sampling rate of 8KSPS. If I w...

changing sampling rate of filter coeficients

I need to implement a particular filter that has 240 taps and it works/designed for a sampling rate of 125kHz. I want to change the sampling rate of the filter from 125kS/s to 250kS/s to match the the hardware I am using, which operates at 250kS/s if i run the filter as is (at 250kS/s), the ...

sampling theorem

how to generate a pulse train for sampling a signal? ...

Problem in Sampling

Dear All, I have one problem in real time signal processing. My signal frequency is 4000Hz and the sampling frequency is 8000Hz. Actually it should be more than 8KHz. Becasue of that i am loosing the zero resting points of the sampled signal. With out increasing the sampling frequency ,...

Re: Sampling in short bursts?

Hello Helmut, > > I’m wondering what rules applies if I’m sampling a signal in short bursts? > Lets say I want to sample a level and I do that by sampling 10 sample points > at 1 µs apart. Then I calculate I mean value of these 10 points. The > sampling frequency in the bursts are 1 ...

Re: interpolating every 4th sample

doh ... wrote: > Assume I have a 48Khz samplerate audio stream, and every fourth sample is > lost. The original material > was filtered to about 22KHz. If the original were filtered at less than 18kHz you should be able reconstruct it correctly. Your signal has a non-uniform 36kHz sampli...

Re: low frequency FFT

Hi, When doing FFT analysis there are two main things you have to consider: 1) the maximum frequency that you can represent based on your sampling rate and 2) the frequency resolution The maximum frequency you can analyze in the FFT is equal to half your sampling frequency. If you want you...

Sampling a gyro and alias filtering?

I want to sample a gyro and then integrate the angular rate to get the angle. When sampling the signal from the gyro, how important is it to filter away frequencies higher than half the sampling rate? I should have at least enough attenuation at the sampling frequency (Fs) so that a...

integration of a continuous function

Hi, it's well known that sampling a continuous function according to the sampling theorem requirements, you get all the information on the contunuous function just from the samples. now, if you have to get an accurate estimate of the integral of the continous function from samples satisfying the ...

Sampling Time Difference in OFDM Demodulator

Dear all, in my diploma thesis i am realizing an ofdm modem. i am working with two adsp bf533 ez-kit-lites. one as transmitter and one as receiver. for d/a and a/d conversion i use the implemented audio codec. this works with nominally 48khz. and here is my problem. these 48khz are only a nomin...

Sinc Non-uniform Filtering

Hi all, At the moment I am working on interpolation filters for bandlimited signals. I was wondering whether anyone knows if there is a generalization of the sinc based interpolation method for a recurrent sampling error. For example the sampling times could look like t = [0.99 2.02 3....

Maximum sampling speed c6711

Good Day, First my apology for not using right terms(not familiar) I have bought a c6711 from ebay. I need to know some thing about it. What is the maximum sampling rate I could achieve. I have used sound card in Linux for data acquisition(voice) maximum sampling speed with my laptop was 1...

Maximum sampling speed c6711

Good Day, First my apology for not using right terms(not familiar) I have bought a c6711 from ebay. I need to know some thing about it. What is the maximum sampling rate I could achieve. I have used sound card in Linux for data acquisition(voice) maximum sampling speed with my laptop was 1...

non-uniform-sampling

Hi all, I would like to know if there is an easy method to do the following: I have a signal of, say, 10ms, sampled at 32kHz (320 samples). I would like to convert this to a signal sampled with a varying sampling rate, for example, starting at 16 kHz, going down to 4 kHz at the end. This w...

Cascading filters with different sampling frequencies.

Hello, I have two filters, one designed for a sampling frequency of 16kHz and the other for a sampling frequency of 8kHz. The type and kind of filters (FIR/IIR, HP/LP/Notch) is irrelevant. I need to plot the overall transfer function of this cascaded pair. What changes do I have to make (in t...

Sampling theorem

Hello, i feel confuse with sampling theorem. I know that if i respect sampling theorem : using sampling frequency above 2*the lowest frequency inside the incoming signal then the signal can be reconstructed from the sequence of values (excuse my poor english). In other word no information is ...

Does anyone have any reference to sampling distortion?

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 criterio...