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bessel space

If I transform the image to bessel space before calculate it's derivative: x = -10:10; T = besseli(x,s,1); im = imfilter(im,T'*T,'symmetric','same','corr'); Can it(bessel filter) surpress the noise introduced by derivative filters? ...

image filtering using bessel function/filters

Hi, I have been asked to design a program in Matlab which calculates the FFT of an image, then defocus the image using a Bessel filter, and reconstruct the defocussed image. Now, I find that only analog models of Bessel filters are available in Matlab, though i found a link to a pdf which shows v...

problem math bessel function

All, I have a series of other questions, but before i get to those ones, i'm stuck on one part of an equation that appears on page 304 of Digital Communications 4th Ed, Proakis. It's equation 5.4-18 and i can't seem to understand how the equality between the integral of the exponential funct...

bessel filter

does any body know how to determine the analog prototype of a bessel filter??? thanks ...

Bessel function simplification problem

All, I'm trying to simplifiy the following equation for the zero'th order modified Bessel function of the first kind. I'm using the approximation for the Bessel function as Io(z) = exp(z)/sqrt(2*pi*z) I would like to have the natural logarithm of this function log(Io(z)) = log(exp(z) ...

Help me with bessel filter concepts

I am implementing a Crossover in c sharp platform. I have already implemented 24th order Butterworth and Linkwitz Riley filters. Now I need to implement 24th order Bessel filter with cascaded biquad sections. Can any of you help me with the procedure? Regards Gangadhar ...

Higher order Bessel filter

Can anybody give me an idea on how to implement nth order bessel filter with cascaded biquad sections? I am able to implement higher order Butterworth with cascaded biquads by following equations given in the link http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt I found that to design fi...

pdf of product of two dependent rv

Hello, I am facing problem in finding the pdf of Z= AB+CD, where A, B, C, D are independent normal random variables with zero mean and uneqaul variances. I could bale to find out the pdf's of each term (i.e. AB or CD). It is a well known result that AB has a pdf of modifie...

Re: reconstruction filter

I am not using a Bessel filter, but an elliptic filter. I dont want to use an dds ic as I am going to use an FPGA to do the DDS so I can generate other waveforms and arbitrary waveforms. I will have to use a Bessel filter for the aribitray because of the time domain characteristic. ...

Parametric description of Transfter function for 4th order Bessel filter

Hi, Does anyone know of a parameteric description for the transfer function (in Laplace domain) of a 4th order Bessel Thompson LPF, in terms of its 3dB bandwidth? If not, is there an empirical way to scale the filter coeffs to get a specific 3dB cut off point? Thanks, Venugopal ...

Re: Band limited function zero crossings, how many?

"Bob Cain" wrote in message news:c12t9o0ddg@enews3.newsguy.com... > > Do you know of applications wherein the prolate spheroid > decomposition has been used? > > > Bob > -- Hello Bob, I have a sort of answer. IIRC, when various types of windows were being designed one optim...

Re: Why window in time domain before FFT?

On Nov 3, 3:23 pm, robert bristow-johnson wrote: .> ... .> Kaiser tried (and .> succeeded very well) to put an optimal expression of this tradeoff, .> getting the best side-lobe performance for a fixed main lobe width, .> and then even introduced a window shape parameter (called "beta"...

Re: a question about fft in matlab

nic@gmail.com wrote: > hello guys, > > This may be a simple question for some of you but I am confused and > will really appreciate your help. > > I have a semi circular 1D signal (assuming all values outside the > circular diameter are 0). I want to recover the width of the signal ...

Help on cascaded filter freq correction

I've figured out the cutoff frequency correction factor necessary to force a 2-pole Bessel lowpass filter to exhibit 3 dB of power attenuation at the cutoff frequency I specify, for a single pass of the filter. The problem is, if I stack up multiple passes, I can't seem to get it right. Here...

Re: Hi, in DSP what do U mean by a 'Freq Component'...

Jerry Avins wrote: > shakes_ck wrote:(snip) > > By the way, Just like "Any signal can be expressed as the sum of > > sinusoids", Is it also possible to "express any signal as the sum of > > 'some other'(Non-Sinusoid) signals".....I mean "Sinusoids" is the > > only solution OR are there...

THD digital FM demod

Hi, I have designed a digital FM demodulator... I have a 70 MHz FI signal that I downconvert to baseband This demodulator works fine with Analog Bessel 24 order filter on I and Q signals before demodulating. When I change this filter with a digital FIR filter (phase lineartity) I have a ...

KB-Window

What is the identity (formula) of a Kaiser-Bessel window. I need something like W[n] = F(n,alpha)= .........? ...

Recipes for non-ripple 2-pole filters available

For the newbies here (like me): I have compiled recipes (step by step instructions) for coding three kinds of 2-pole digital filters, both low-pass and high-pass, complete with correction factors to ensure that the 3 dB cutoff frequency stays where you put it when you cascade filters togethe...

Re: Linear Phase via 'Phase Cloning' New Method

Hi, If you are interested then you can work on the following problem. Linear phase IIR design (not the bessel one, bessel has strong rolloff in passband). Normally in matlab, we do this design as 2 step process: 1. Design IIR filter (elliptic/chebyshev/butterworth) 2. Design the...

bartlet

hi folks, i have a term project about high-pass bessel filter with fstop = 200Hz and fPass = 400Hz, there's no big deal in "iir" design, i could overcome it, but at the "fir" design i was asked to perform this by a "bartlett window" and my brain is almost to explode, i can't find any articles, any t...

Anti-Aliasing filter

If you are estimating time-delay bewteen two microphones would it be better to use a Bessel filter for anti-aliasing rather than a Butterworth due to the approximate linear phase. Wang King ...

Re: simple average filters...

Or could it be a simple scaling factor? If I change the length of the FIR, the curve just stretches on the sample axis => the ratio between zero crossings and 3 dB cutoff frequency remains the same. I'd say it's around 0.4: http://www.elisanet.fi/mnentwig/sinc.png A related question: Is t...

Re: FIR coefficients for Bessel analog filter

Hi, In fact I'm deliberately trying to obtain the slow rolloff in attenuation in the stopband and yet have no ripples in the passband. I find that when I use the FDAtool in Matlab, the filter always has a very sharp transition in the stopband. Anyadvice on how to obtain a symmetric FIR which ...

Re: What Nyquist Didn't Say

Tim Wescott wrote: > 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...

Cascade Form IIR Filters

hi! All, i would like some info on implementing cascade form IIR filters...does matlab support it???...as far as i can understand butter,cheby1,cheby2,bessel,ellip generate coefficients in the direct form...how do i implement the cascade form... TIA bngguy ...

Re: Wireless channel modelling

Hi Raymond, Yes, that makes sense, but I still have questions: So ultimately, what I'm trying to do is generate a sequence of random variables that have Jakes' bessel function autocorrelation. Each random value represents the phase difference and antenna attenutation of one multipath, so in...

Re: Reconstruction Filter behind DAC

hi, I thought design a low pass bessel (good group delay) filter with a cutoff frequency of 350 MHz because i have to generate an IF frequency until 350 MHz. I have seen that integrated interpolation filter can help to reduce the order of the reconstruction filter. guillaume ...

how to get rid of ringing with IIR notch filters?

Hello, I have an IIR notch filter ( i.e. bandstop ), that rings like crazy whenever a transient signal comes through ... which is very unwanted for my application. Anybody have any ideas how to get around this? I have to stick with IIR form filters. I've tried all the various standard desi...

Re: Unusual DFT Windows

Michael Soyka wrote: > a good reference > would be Richard Hamming's book "Digital Filters" which I think is now > published by Dover (I have the Prentice-Hall 3'rd edition). It is indeed published by Dover, it is available for less than $11 at amazon.com. To me, the (Dover) book just...

Re: Bandpass filter techniques

Isaac Gerg wrote: > Some bandpass filters I have heard of: > 1. Chebyshev > 2. Butterworth > 3. Raised Cosine > > > What are the attribtues of theses filters that make ones more useful > than another in a given sitation? > > Iasac Google will turn up lots of information. ...

Re: Sample Rate Conversion by non integer factor

"Ronald H. Nicholson Jr." wrote in message news:cc1q5u$8k1$1@blue.rahul.net... > In article , > > On a fast > PC you may not need to do this, as a well tuned math library can often > calculate the window and Sinc tap coefficients in real time. Just curious, how well does this work...

Plotting amplitude spectra of PWM based on Double Fourier Series

Hello, I'm trying to understand a paper I've read ("A Review and Comparison of PWM methods for Analog and Digital Input Switching Power Amplifiers"), which compares different PWM methods. I've been trying to plot the amplitude spectra of different natural pulse width modulated (NPWM) ...

Re: uneven quantization

On Apr 15, 5:29 pm, Jerry Avins wrote: > dragonboy....@gmail.com wrote: > > I would like to know how can I make an uneven quantization !! > > > I would like to get straight lines (approximation of the random > > curve) !! It is some sort of quantization where I have also average > ...

Re: Low freq "analog" of Nyquist? ( possibly naive question )

"Fred Marshall" wrote in message news:tj4Na.2297$Jk5.1256042@feed2.centurytel.net... > I didn't ever say anything about differential equations - although I know > that you had earlier which I didn't understand but didn't worry about at the > time. I figured perhaps there was a nice a...

Re: Distrubution of noise times noise

Hi, On 30 nov, 05:40, "spasmous" wrote: > If I have two signals that are corrupted with Gaussian random noise and > I multiply them, what is the noise distribution called? > > x1 = s+n1 > x2 = s+n2 > x1*x2 = s*s+(n1+n2)*s+n1*n2 > > Is noise times noise (n1*n2) the focus of any ...

Re: non-integer frequency

On 4 Okt, 01:34, Randy Yates wrote: > "Not orthogonal" means not orthogonal in any > coordinate system. No. The complex exponentials exp(jwn) are orthogonal in the sense = 0 n =/= m where means "the inner product between a and b" in the carthesian coordinate system only. ...

newbie filter question

Hi everyone, Just got handed a 600000 line software application with lots of DSP. I am trying to understand a few things and as I am new to DSP, it is a bit complicated. Here is a scenario. There is a signal that is being fed into a cascaded Bessel filter bank that splits it into 0-60 Hz, 6...

Re: Half sinc IIR?

"Bob Cain" wrote in message news:401C3ECB.9ED0D112@arcanemethods.com... > > > A sufficiently high-order Butterworth lowpass should do as an approximation. > > Do you think that the best? I've done a lot of work with > real world IR's and transfer functions but almost none with > ...

Re: Demod Woes

I don't have a specific answer but some general suggestions... you know of course that the BW of an FM signal in considerably wider compared to the deviation? maybe as much as 270 kHz in your case...there is nothing in the system that restricts the BW too much? is the distortion worse with ...

Re: A better window than hanning

In article , "Fred Marshall" wrote: > > > I don't think that overlap and the window selection are related. But, > someone somewhere may have shown that it matters the tiniest bit. For what > you're doing I don't see how it can matter. > It does if you go back to the time domai...