## easy resampling bandwith question ...

Started by in comp.dsp16 years ago 5 replies

hi all, let's say i want to resample to 4/5 the input samplerate, i.e. interpolate 4X then decimate 5X. for both steps lowpass filters need...

hi all, let's say i want to resample to 4/5 the input samplerate, i.e. interpolate 4X then decimate 5X. for both steps lowpass filters need to be designed. according to dspguru.com, it is sufficient to 1. determine cutoff freq. for the interp. filter 2. determine cutoff freq. for the decim. filter 3. choose the lower of the 2 cutoff freqs to design *one* resampling FIR filter. so...

## FIR filtering using a lookup table

Started by in comp.dsp16 years ago 5 replies

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

## beginer question

Started by in comp.dsp16 years ago 2 replies

How may I determine cutoff frequency of FIR filter? Thanks Marcin

How may I determine cutoff frequency of FIR filter? Thanks Marcin

## HELP RE: FIR filter designing

Started by in comp.dsp16 years ago 1 reply

Hallo, please listen my story . One day i went to a professor's room for asking a job..there i told him about myself .then he...

Hallo, please listen my story . One day i went to a professor's room for asking a job..there i told him about myself .then he asked me to design a Finite Impulse Response Filter using VERILOG. !! I said OK for that moment !! He is not at all giving me any kind of guidance for designing it.I am absolutely novice in filter design. Now i was struck at the begining itsel...

## Minimum-Phase FIR Filters Tutorial in DSPguru.com

Started by in comp.dsp16 years ago 2 replies

Hello, I am looking for a way to get the minimum phase version of a FIR filter. I saw the tutorial in...

Hello, I am looking for a way to get the minimum phase version of a FIR filter. I saw the tutorial in DSPguru.com: http://www.dspguru.com/howto/tech/minph.htm The question I have is specifically about the Homorphic filtering method. I've checked one of the sources for this Method (Discrete-Time Signal Processing by A. V. Oppenheim and R. W. Schafer) and there are several differences b...

## How to decide the filter length in ADNC using LMS Algo ?

Started by in comp.dsp15 years ago 6 replies

Hi, How to decide the FIR - filter length (no. of taps) required to design the ADAPTIVE NOISE CANCELLER ? I am using the LMS...

Hi, How to decide the FIR - filter length (no. of taps) required to design the ADAPTIVE NOISE CANCELLER ? I am using the LMS Algorithm.. Thanks in advance...

## Decimation (CIC) filter in VHDL

Started by in comp.dsp16 years ago 4 replies

Hi all, I am currently in the process of designing a decimation filter for a 16bit Sigma Delta ADC. I suspect it will be a CIC filter...

Hi all, I am currently in the process of designing a decimation filter for a 16bit Sigma Delta ADC. I suspect it will be a CIC filter followed by a FIR filter. I am facing great difficulty understanding such filter, as my experience in usually with analog circuits, and not DSP. My question basically, is there any free Matlab or VHDL code to get me started simulating either the whole...

## Basic Filter Query

Started by in comp.dsp16 years ago 2 replies

Hi, The order of a digital filter is the number of previous inputs (stored in the processor's memory) used to calculate the current...

Hi, The order of a digital filter is the number of previous inputs (stored in the processor's memory) used to calculate the current output. My doubt is, how can one estimate the current output based on the previous inputs ? E.g in Adaptive Noise cancellation, if FIR filter is used, then the output of the filter is, y[n] = x[n]*h[0] + x[n-1]*h[1] + ... + x[0]*h[n] If x is the nois...

## Bandpass FIR Filter

Started by in comp.dsp16 years ago 19 replies

I have a basic doubt regarding FIR Filter implementation. The input to my FIR filter is the data(16-bit out from ADC sampled at 20 KHz). i.e...

I have a basic doubt regarding FIR Filter implementation. The input to my FIR filter is the data(16-bit out from ADC sampled at 20 KHz). i.e this data represents the amplitude of the sampled input signal. My doubt is "whether the output of the FIR filter denotes the amplitude or frequency of the filtered data? Please clarify Regards, Nitesh

## Basic Filter Question

Started by in comp.dsp16 years ago 1 reply

Hi, The order of a digital filter is the number of previous inputs (stored in the processor's memory) used to calculate the current...

Hi, The order of a digital filter is the number of previous inputs (stored in the processor's memory) used to calculate the current output. My doubt is, how can one estimate the current output based on the previous inputs ? E.g in Adaptive Noise cancellation, if FIR filter is used, then the output of the filter is, y[n] = x[n]*h[0] + x[n-1]*h[1] + ... + x[0]*h[n] If x is the nois...

## Minimum phase FIR filter algorithm

Started by in comp.dsp16 years ago 3 replies

Hello, I am looking for algorithms to calculate a minimum phase FIR filter from a desired frequency responce or from zero phase impulse...

Hello, I am looking for algorithms to calculate a minimum phase FIR filter from a desired frequency responce or from zero phase impulse response. Thank you, Frederic

## Halfband filter delay!

Started by in comp.dsp16 years ago 4 replies

Hi! By definition the FIR filter delay is: (N-1)/2 The halfband filter has every other sample exactly zero. If the first and the last sample...

Hi! By definition the FIR filter delay is: (N-1)/2 The halfband filter has every other sample exactly zero. If the first and the last sample of the filter are exactly zero. What is the delay of the filter? (N-1-2)/2 ? Thats not what I am getting. Why? Thanks! Atmapuri

## Multi-stage filter delay!

Started by in comp.dsp16 years ago 6 replies

Hi! I am trying to compute the delay of a multi-stage half band FIR filter bank (upsampling by factor 2 in each stage). (N is number of...

Hi! I am trying to compute the delay of a multi-stage half band FIR filter bank (upsampling by factor 2 in each stage). (N is number of taps). With one stage (half band filter) I get: (N1-1) /2 + 1. With two stages: (N1-1)/2 * 2 + 1 + (N2-1)/2 - 4 On stages higher then 2 filter length is equal to N2. But I am having trouble deriving the general formula... Any ideas? Thanks! A...

## how to compute coefficient of FIR filter?

Started by in comp.dsp16 years ago 1 reply

Hi, How to compute the coefficient of FIR Filter? Since i am new to filter design, can any one suggest some good materials for...

Hi, How to compute the coefficient of FIR Filter? Since i am new to filter design, can any one suggest some good materials for beginners? Thanks chi

## Between min. phase and lin. phase filters

Started by in comp.dsp16 years ago 15 replies

Hi comp.dsp members, I have one filter design question. Are there any methods to design a FIR filter with the specified magnitude response, so...

Hi comp.dsp members, I have one filter design question. Are there any methods to design a FIR filter with the specified magnitude response, so that its phase response is somewhere between min. phase and linear phase? In other words, are there any ways to control the ratio of post- and pre-ringing in the filter's impulse response? Maybe it's possible for some special cases? (e.g. lowpass fi...

## FIR coefficients

Started by in comp.dsp16 years ago 10 replies

hello all, I am currently working with FIR filter.Here i get the coefficients as deciamal values...

hello all, I am currently working with FIR filter.Here i get the coefficients as deciamal values like -0.000467744403 0.000802870932 -0.000000000000 -0.001041888331 0.000768540238 0.000930750510 -0.001834127637 0.000000000000 0.002708566451....... i have to perform the filtering with 15 bit input line and 16 bit output line. can anyone suggest me how to store these coefficients in m...

## Naive FIR filter question

Started by in comp.dsp16 years ago 7 replies

Hi Guys, I have a simple (I think) filtering question. I've programmed (years ago) microcontrollers, but I've never programmed any...

Hi Guys, I have a simple (I think) filtering question. I've programmed (years ago) microcontrollers, but I've never programmed any of the modern DSP chips with their "zero-overhead looping" and single-cycle multiply-and-accumulate features. (I know, I know. I should get a DSP starter kit!) So the DSP chips are efficient for implementing FIR filtering. Am I correct in ass...

## The system that requires largest!

Started by in comp.dsp16 years ago 29 replies

Though it is not very good (rather stupid) to ask the following questions; I thought this could be a pre-Xmas fun! 1. What is the largest FFT...

Though it is not very good (rather stupid) to ask the following questions; I thought this could be a pre-Xmas fun! 1. What is the largest FFT size(point) ever used so far and where(Application)? 2. What is the largest QAM constellation ever used commercially so far and where(Application)? ? 3. What is the largest FIR filter taps used so far and where(Application)?. Real time constrain...

## Remez algorithm and filter lengths

Started by in comp.dsp16 years ago 7 replies

Hi all. I was just involved in a thread over at comp.soft-sys.matlab where I got involved with the Remez algorithm. The matlab SP toolbox...

Hi all. I was just involved in a thread over at comp.soft-sys.matlab where I got involved with the Remez algorithm. The matlab SP toolbox version is the only implementation of the Remez algorithm I have used, and it requires the user to specify the length of the FIR filter to be designed. Now, does the Remez algorithm generally require the filter length to be supplyed by the user...

## emphasis coefficients

Started by in comp.dsp16 years ago 1 reply

Hi all ! I am looking for the coefficients for a FIR filter to compute the pre-deemphasis 50/15 us. Does anybody know them ? Are there any...

Hi all ! I am looking for the coefficients for a FIR filter to compute the pre-deemphasis 50/15 us. Does anybody know them ? Are there any IC that can do it without having to use a DSP ? Thanks in advance ! Sam