Does anyone have a *good* explaination of B-Splines? Links to paper would be great, but ideally I'm looking for someone to put B-Spline theory...

Does anyone have a *good* explaination of B-Splines? Links to paper would be great, but ideally I'm looking for someone to put B-Spline theory in basic english! I have looked at numerous papers and online documentation, but they usually jump right to some advanced math and terminology. My basic understanding is that it is a piecewise polynomial and can be used for smooth interpolation of sign...

Hello all, This is a question which probably boils down to "what am I missing?". It seems to be commonly stated that for interpolation or...

Hello all, This is a question which probably boils down to "what am I missing?". It seems to be commonly stated that for interpolation or decimation, it's generally more computationally efficient to perform the operation in multiple stages, i.e. factorise the rate-change factor, and design a lower-order filter for each stage. I completely accept that designing the individual filters in ...

I had a question posed to me today that got me thinking. Here was the question: "If the signal is oversampled by 10 x fs and then only every...

I had a question posed to me today that got me thinking. Here was the question: "If the signal is oversampled by 10 x fs and then only every 10'th data point is used for the final data set (without any filtering of the rest of the data points) will there be any difference in the noise from data that is sampled at only fs? The result is the same number of points." My answer was yes, ...

hi.. This is my 1st mail to this group. I am trying to do a polyphase filter bank in dsp and thn get it into FPGA.. this is not for decimation...

hi.. This is my 1st mail to this group. I am trying to do a polyphase filter bank in dsp and thn get it into FPGA.. this is not for decimation or interpolation. This is mainly done for radio telescope back end in which we need 4 or 8 small channels from a big IF coming in. Can any one help me to find wht exactly is polyphase filter. ie whether the filters in the bank is linked with each othe...

I'm currently designing CIC filters, I found that almost all are referring to the following paper: E=2E B. Hogenauer, =E2=80=9CAn Economical...

I'm currently designing CIC filters, I found that almost all are referring to the following paper: E=2E B. Hogenauer, =E2=80=9CAn Economical Class of Digital Filters for Decimation and Interpolation=E2=80=9D. IEEE Transactions on Acoustics, Speech, and Signal Processing, 29(2):155-162, April 1981. I don't have access to any source for it. Would somebody send it to me by email? Thanks in ...

I'm primarily an analog and logic designer, so please bear with my lack of DSP chops. I've got an application where I'm looking to feed a DAC...

I'm primarily an analog and logic designer, so please bear with my lack of DSP chops. I've got an application where I'm looking to feed a DAC at a constant 128 MSPS from a data stream that will be a power of 2 fraction of that (64 MSPS down to 250 kSPS). I'd like to be able to get pretty close to the Nyquist limit (say 0.4 or so) of whatever the original data rate is. It seems so far li...

Hi all. I'm doing some work on a commercial black box system with three sensors that are being sampled at 10 Hz. One of the sensors are...

Hi all. I'm doing some work on a commercial black box system with three sensors that are being sampled at 10 Hz. One of the sensors are running freely, while the two other sensors are polled by a linux computer. For one of the polled sensors there is a unpredictable delay from when I request data to it is being received. This means that I'm basically getting the information from the ...

This is due to Whittaker E. T. Whittaker, On the functions which are represented by the expansions of the interpolation theory, Proc. Roy....

This is due to Whittaker E. T. Whittaker, On the functions which are represented by the expansions of the interpolation theory, Proc. Roy. Soc. Edinburgh 35 (1915), 181-194 http://www-gap.dcs.st-and.ac.uk/~history/Mathematicians/Whittaker.html and to Kotelnikov V. A. Kotelnikov, On the carrying capacity of the ether and wire in telecommunications, Material for the First All-Un...

Hi, am I right to say that the higher the order of a B-spline, the more continuous derivatives it has? And that sinc interpolation has...

Hi, am I right to say that the higher the order of a B-spline, the more continuous derivatives it has? And that sinc interpolation has infinite continuous derivatives? What about windowed sinc? Is the Lanczos a good choice for an interpolator whose goal is to have as many continuos and smooth derivatives as possible, and to pass through the points? Thanks, Mike

Hello, If a signal is usampled by a factor L & then passed through a filter to interpolate & now I downsample this signal by N where L> N,(or...

Hello, If a signal is usampled by a factor L & then passed through a filter to interpolate & now I downsample this signal by N where L> N,(or decimate), will my resulting signal have an upsampling rate of : L/N ? Will there be any change to the statistics of this signal? If my original signal was gaussian distributed,will the new signal be gaussian distributed too? Looking forward for a reply

Hello , I`m doing a research for multi-rate technique and i need this 2 very important basic paper that i did not find in web : 1) Croisier,...

Hello , I`m doing a research for multi-rate technique and i need this 2 very important basic paper that i did not find in web : 1) Croisier, A. ,Esteban , D., and Galand "Perfect channel splitting by use of interpolation/decimation/tree decomposition techniques" Int.Symp.on Info.,Circuit and Systems, Patras,Greece, 1976 2)Ramstad,T.A. "analysis/synthesis filter banks with critical samp...

Hi, In the TX side of our system, we have data being passed through the pulse shaping filter (Root Raised Cosine) which is being sampled at...

Hi, In the TX side of our system, we have data being passed through the pulse shaping filter (Root Raised Cosine) which is being sampled at 1 Mhz. It is a standard RRC...ie basic FIR structure. However, we need to interpolate to get the sampling frequency up to 8Mhz. I have been told my options are to use a polyhase filter structure, however it means us going back to the drawing board. ...

Hi, I have an acoustic transducer with fairly simple analog frontend to which I'm building a digital modulating logic. It's custom stuff so...

Hi, I have an acoustic transducer with fairly simple analog frontend to which I'm building a digital modulating logic. It's custom stuff so we can't rely on anything OTS (e.g. interpolation reconstruction filter) and we don't have board space to do this in analog. So basically I need to make everything happen in the digital domain. It so happens that I have plenty of on-chip ram. So I en...

I'm working on a "problem" that got me thinking. As the purpose of attempting the "problem" was education that's good. I have 96 data...

I'm working on a "problem" that got me thinking. As the purpose of attempting the "problem" was education that's good. I have 96 data points. I desire: 1. approximation of 97th (but NOT 98th or greater). 2. interpolate 28 intervening data points, including between points 96 and 97. I know a priori that: 1. the function and ALL derivatives are continuous. 2. the funct...

Hello. I am reading "The Scientist and Engineer's Guide to Digital Signal Processing" by Steven W. Smith and I have a question. In the chapter...

Hello. I am reading "The Scientist and Engineer's Guide to Digital Signal Processing" by Steven W. Smith and I have a question. In the chapter 3 (http://www.spectrumsdi.com/ch3.pdf) p.60: "The 8 kHz data is pulled from memory and converted to a 64 kHz sampling rate, a procedure called interpolation. This involves placing seven samples, with a value of zero, between each of the samples o...

Hi I have a data set obtained by combining elements from 3 different arrays. The elements in each array are repeating at a same interval...

Hi I have a data set obtained by combining elements from 3 different arrays. The elements in each array are repeating at a same interval but after combining the array, the data is not uniformaly spaced,e.g. DATA1 = 0 10 20 30 40... DATA2 = 2 4 6 8 10 DATA3 = 11 12 13 14 15... combined data = 0 2 4 6 8 10 11 12 13 14 15 16.... And I have a complex value associated to each data value. ...

Hi, Currently I am using a polyphase FIR filter to perform an interpolation. To gain performance I have in mind to redesign the original...

Hi, Currently I am using a polyphase FIR filter to perform an interpolation. To gain performance I have in mind to redesign the original filter with the principle of a lookup table. Does anyone know where I can find some helpful information of how to implement this principle? Regards, Ellegaard

Hi all! According to the Heisenberg Uncertainty principle, the frequency resolution is limited in a finite time frame. However, if a sinusoid is...

Hi all! According to the Heisenberg Uncertainty principle, the frequency resolution is limited in a finite time frame. However, if a sinusoid is the only significant component in its vicinity, zero padding can be used to get a better resolution of the DFT. This makes the spectral shape and place of the sinusoid more clear and enables more accurate parameter estimation. Does anybody know wh...

I'm working on a paper about interpolation that I threatened to do long ago. I'm trying to say that a spectrum that has nonzero (or not small)...

I'm working on a paper about interpolation that I threatened to do long ago. I'm trying to say that a spectrum that has nonzero (or not small) samples at or near fs/2 is problematic. But I'm having a bit of trouble saying why it's bad necessarily. One thing one can say is that it's likely that the spectrum was not properly bandlimited before sampling and spectral aliasing is likely to h...

Here's a little something I'd like to get suggestions for so I can try them. My problem is the following, for an original image of...

Here's a little something I'd like to get suggestions for so I can try them. My problem is the following, for an original image of given dimensions, you're only given (for example) 6 lower resolution images and by combining them try to obtain something as close as possible to the original full resolution image. Here are in my example the characteristics of the 6 low resolution images : 1st...