## flanger effect, audio interpolation

Started by in comp.dsp16 years ago 1 reply

Hey, I'm implementing a flanger effect as part of a guitar effects processor on an ADSP-21364 development board. A Flanger effect is produced...

Hey, I'm implementing a flanger effect as part of a guitar effects processor on an ADSP-21364 development board. A Flanger effect is produced by adding a single delay to the current input sample, the length of the delay is dictated by a sin wave which i have in aa lookup table. This implements a comb filter. My problem is that on top of the desired output I am also getting a 'police si...

## Calculating the gain of a comb-resonator bandpass filter

Started by in comp.dsp15 years ago 2 replies

Hi, I'm an computer engineering undergrad with what is probably a simple filter question. I need to simulate in Matlab and provide a...

Hi, I'm an computer engineering undergrad with what is probably a simple filter question. I need to simulate in Matlab and provide a mathematical analysis of a bandpass filter by cascading a comb filter with a resonator. The comb has transfer function: Hc(z) = 1 + r^m*z^-m and the resonator: Hr(z) = z^2/(z^2 - 2*r*cos(omega)*z + r^2) = z^2/((z - r*exp(j*omega))(z - r*exp(-j...

## my first questions about CIC filter input datatype limit in Matlab

Started by in comp.dsp14 years ago 1 reply

hi everyone, when I use FDATools to design a CIC(cascade integrator comb)filter the input datatype must be signed fix point. but after our...

hi everyone, when I use FDATools to design a CIC(cascade integrator comb)filter the input datatype must be signed fix point. but after our sigma delta modulator, the output is in double type. how could I transfer between them in order to use CIC filter in Matlab simulink. forgive me my poor expressions and Thanks a lots zcambrdige

## How to add two add two correlated signals, but NOT have comb filtering...

Started by in comp.dsp13 years ago 12 replies

I have two audio signals that are correlated but one of them is a delayed version of the first signal (let say by 10ms). Now I want to sum...

I have two audio signals that are correlated but one of them is a delayed version of the first signal (let say by 10ms). Now I want to sum them together, but of course, this produces a nasty comb filter. So the first thing that sprung to mind was to allpass the "first" signal to approximate the 10ms delay of the second. This works good because I can tolerate some combing but at higher frequ...

## Width of comb filter teeth

Started by in comp.dsp13 years ago 3 replies

Hi all. Does anyone know how to change the width of a feedback comb filter's teeth? From the general idea on wikipedia, it seems like it is only...

Hi all. Does anyone know how to change the width of a feedback comb filter's teeth? From the general idea on wikipedia, it seems like it is only possible to change the delays and the gain. Thanks

## Width of comb filter teeth

Started by in comp.dsp13 years ago 6 replies

Hi all. Does anyone know how to change the width of a feedback comb filter's teeth? From the general idea on wikipedia, it seems like it is only...

Hi all. Does anyone know how to change the width of a feedback comb filter's teeth? From the general idea on wikipedia, it seems like it is only possible to change the delays and the gain. Thanks

## QUESTION FOR Rick Lyons Re: tips and tricks book

Started by in comp.dsp12 years ago 12 replies

Hi Rick, I was reading a chapter in the DSP tips and tricks book on using comb filtering after two-level saturated sampling for FSK...

Hi Rick, I was reading a chapter in the DSP tips and tricks book on using comb filtering after two-level saturated sampling for FSK demod preprocessing. The text said a comb filter equivalent could be made with a direct path and a delayed path input into an XOR gate because the inputs were binary. However, for the binary inputs, the outputs of an XOR are normally 2 level, while the output...

## Notch comb filter coefficients

Started by in comp.dsp11 years ago 4 replies

Hi all. I've found in MATLAB help that a notching comb filter has following tranfser function: H(z) = b*(1+z^(-N))/(1+a*z^(-N)) where N is...

Hi all. I've found in MATLAB help that a notching comb filter has following tranfser function: H(z) = b*(1+z^(-N))/(1+a*z^(-N)) where N is the number of notches. How to determine coefficients a and b with respect to real-world parameters such as sampling frequency, notch frequency and notch bandwidth/resp. attenuation? I don't have the filter toolbox and therefore not the 'iircomb' functio...

## generalized comb filters: help with terminology...

Started by in comp.dsp10 years ago 10 replies

okay, we know about comb filters. https://ccrma.stanford.edu/~jos/pasp/Comb_Filters.html the simplest are feedforward comb...

okay, we know about comb filters. https://ccrma.stanford.edu/~jos/pasp/Comb_Filters.html the simplest are feedforward comb filters: y[n] = b_0*x[n] + b_M*x[n-M] H(z) = b_0 + b_M*z^-M then there are feedback comb filters: y[n] = b_0*x[n] - a_M*y[n-M] H(z) = b_0 / (1 + a_M*z^-M) now, isn't it still a "comb filter" when you combine the t...

## CIC equations mystery

Started by in comp.dsp7 years ago 7 replies

Hi All 1) According to M.Donadio article "Cascaded Integrator-Comb Filter Introduction" Hf = (sin(pi*f*M)./sin(pi*f/R)).^N; where Hf =...

Hi All 1) According to M.Donadio article "Cascaded Integrator-Comb Filter Introduction" Hf = (sin(pi*f*M)./sin(pi*f/R)).^N; where Hf = amplitude response at frequency f M = number of comb delay stages N = number of cascaded comb/integrator pairs R = rate change(up or down) 2) According to Rick Lyon's article "Understanding cascaded Integrator-comb" Hf = (sin(pi*f*D)/sin(pi*f)).^M ...