## How to scale second order IIR filter koefficients?

Started by in comp.dsp13 years ago 15 replies

How can I scale the coefficients of an second order section IIR filter so they are within -1 to +0.99999988079071 ? When I calculate a...

How can I scale the coefficients of an second order section IIR filter so they are within -1 to +0.99999988079071 ? When I calculate a filter in MATLAB fdatool I get some coefficients that are > 1.

## Symmetric phase response of an IIR allpass.

Started by in comp.dsp13 years ago 11 replies

Hi all, Does anybody know if there is a way to design a symmetric phase response allpass iir filter? I'm able to design a filter with an...

Hi all, Does anybody know if there is a way to design a symmetric phase response allpass iir filter? I'm able to design a filter with an approximately accurate phase response compared to a prescribed phase response for the positive frequencies. However, plotting the phase response of the filter (e.g. with fvtool(b,a) in matlab) for the full -pi to pi range the negative phase response is...

## How to best detect tone amplitudes quickly?

Started by in comp.dsp13 years ago 8 replies

Hello I need to be able to detect the amplitude of a frequency faster than 6ms (the measurement is not made continuously). The sample...

Hello I need to be able to detect the amplitude of a frequency faster than 6ms (the measurement is not made continuously). The sample frequency is 46800 Hz and the frequency to detect is 1650 Hz. If I use a IIR filter it has an transient period before it gives a steady state output, so I must wait long enough for the output to reach steady state before I measure the amplitude...

## IIR oscillator or cos(Wn)

Started by in comp.dsp13 years ago 11 replies

Hi All, I am new to DSP, i have few qestions which many of you may find stupid but an early response is desired 1. cos(Wn)=cos(...

Hi All, I am new to DSP, i have few qestions which many of you may find stupid but an early response is desired 1. cos(Wn)=cos( 2*pi*(Fc/Fs)n) is used in some documentation for oscillator, whereas some documenatin revelas use of IIR coeffecients for oscillator implementation. which apprach is correct? (i have understanding of FIR and IIR filter ) 2. If I use cos(Wn) for with appropriate pa...

## IIR Filter Realizations

Started by in comp.dsp13 years ago 16 replies

In most books, block diagram realizations of IIR filters are shown - these include Direct form1 and Direct form II also, transposed realization...

In most books, block diagram realizations of IIR filters are shown - these include Direct form1 and Direct form II also, transposed realization and so on. I was wondering what the point is. Essentially these are all state-space type realizations but in implmenting a filter we just use the difference equation. I can see that if you were implmenting in hardware then you would gain by for examp...

## Design of a Filter

Started by in comp.dsp13 years ago

Hi, I am modelling the physical layer of an 802.11 transmitter (to implement it into an FPGA). At this moment I want to design the...

Hi, I am modelling the physical layer of an 802.11 transmitter (to implement it into an FPGA). At this moment I want to design the digital filter responsible of pulse shaping (before the DAC). My doubts are: 1. FIR or IIR filter?, why?. 2. For each option (FIR or IIR) there are different types of filters (FIR: Raised_cos_Barlett, Raised_cos_Blackmann, etc, ... or IIR: Butterworth, Cheby...

## IIR filter

Started by in comp.dsp13 years ago

Hi, I have developped a Direct Form I RII filter but there is a critical path of one multiplier and four adders.. Is there a best...

Hi, I have developped a Direct Form I RII filter but there is a critical path of one multiplier and four adders.. Is there a best implantation for high speed signal processing... best regards

## Frequency filtering from non stable IIR.

Started by in comp.dsp13 years ago 6 replies

Hi pals, My post title is maybe very weird, but let me expose the situation: I want to filter a real infinite signal x(k) by block...

Hi pals, My post title is maybe very weird, but let me expose the situation: I want to filter a real infinite signal x(k) by block convolution. To do this I have the the frequency response of an IIR filter (called h). The frequency response correspond to : H(k) = B(k)./A(k) (matlab notation ./ => pointwise division) where B(jk) is the 1024pts DFT of a sequence b(k) which has 128pts, same fo

## What is wrong in this IIR filter code?

Started by in comp.dsp13 years ago 19 replies

Hi, Given are following coefficients to a second order butterworth highpass filter with a 3 dB cutoff freq of 4.48 Hz: double a0 =...

Hi, Given are following coefficients to a second order butterworth highpass filter with a 3 dB cutoff freq of 4.48 Hz: double a0 = 1.0; double a1 = -1.999722319818149; double a2 = 0.999722358365939; double b0 = 0.999861169546022; double b1 = -1.999722339092044; double b2 = 0.999861169546022; that is used in the following direct form IIR filter implementation: double Yn, Yn1, Yn2, ...

## OT: Christmas Greetings

Started by in comp.dsp13 years ago 47 replies

Hi everyone, Here's wishin' all you guys a very Merry Christmas and a Happy New Year! Of course, these good wishes are also directed at...

Hi everyone, Here's wishin' all you guys a very Merry Christmas and a Happy New Year! Of course, these good wishes are also directed at any of you who do not celebrate Christmas such as: Muslims, Hindus, God-less atheists, Buddhists, software engineers, Sikhs, Jews, IIR filter designers, Shinto, Democrats, Neo-pagans, transsexual lesbians, U.S. Government employees, Devil worsh...

## Problem of SOS matrix to Transfer Function in IIR Filter Design using Matlab

Started by in comp.dsp13 years ago 3 replies

Hi, everyone, I have to design a IIR filter using FDATOOL in Matlab. And I expert it to workspace as SOS Matrix(SOS) and Scale Values(G). Then I...

Hi, everyone, I have to design a IIR filter using FDATOOL in Matlab. And I expert it to workspace as SOS Matrix(SOS) and Scale Values(G). Then I use function [b,a] = sos2tf(SOS,G) to acquire the Transfer Function. However, it always report error: > > [b,a]=sos2tf(SOS,G) ??? Error using ==> times Matrix dimensions must agree. Error in ==> sos2tf at 52 b = b.*g; I don't know how to handl

## Regarding polyphase IIR filter.

Started by in comp.dsp13 years ago

Dear All, Iam working subband acoustic echo cancellation.In that for subbanding the input signal i used polyphase IIR filter.I...

Dear All, Iam working subband acoustic echo cancellation.In that for subbanding the input signal i used polyphase IIR filter.I searched in net for polyphase IIr filter design.I got some techinical documents related to polyphase IIr filter, I mentioned important links related to documents below. 1 http://users.cscs.wmin.ac.uk/~krukowa/pdf/Paper27.pdf 2http://ieeexplore.ieee.org...

## regarding polyphase IIR filter.

Started by in comp.dsp13 years ago 6 replies

Dear All, This is the my first mail to post our group.Iam working on subband acoustic echo cancellation.In that for subbanding the...

Dear All, This is the my first mail to post our group.Iam working on subband acoustic echo cancellation.In that for subbanding the input signal 2 path polyphase IIR filter is used.I searched for polyphase IIR filter design in net I got some techginical documents.In those documents one documents for 2 path polyphase IIR filter design related to acoustic echgo cancellation, The filter coe...

## IIR filter in 56300

Started by in comp.dsp13 years ago 1 reply

Hi, Can you tel me, is this code can represents IIR filter in 56300 procesor? MOVE #STATES,R0 MOVE #COEF,R4 MOVE #N-1,M0 MOVE #2*N,...

Hi, Can you tel me, is this code can represents IIR filter in 56300 procesor? MOVE #STATES,R0 MOVE #COEF,R4 MOVE #N-1,M0 MOVE #2*N, M4 MOVE #OUT,R1 DO FOREVER , END MOVE X:(R0)+,X0 Y:(R4)+,Y0 REP #N-1 MAC -X0,Y0,A X:(R0)+,X0 Y:(R4)+,Y0 MACR -X0,Y0,A X:(R0)+,X0 Y:(R4)+,Y0 CLR A A,Y1 REP #N-1 MAC +X0,Y0,A X:(R0)+,X0 Y:(R4)+,Y0 MAC +X0,Y0,A X(R0)-,X0 Y:(R4)+,Y0 MACR +Y1,...

## IIR Filter Design

Started by in comp.dsp13 years ago 3 replies

I was given a continous signal x(t) = 1.272*cos(2*pi*50*t)−0.424*cos(2*p*150*t)+0.255*cos(2*pi*250*t) and I generated discrete signal...

I was given a continous signal x(t) = 1.272*cos(2*pi*50*t)−0.424*cos(2*p*150*t)+0.255*cos(2*pi*250*t) and I generated discrete signal {x(n)}, 0

## Cut-off frequency and sampling frequency IIR filter

Started by in comp.dsp13 years ago 2 replies

Hi all, I have a little question... Is there a trade-off beetween the cut-off frequency of an IIR filter and it's sampling frequency...

Hi all, I have a little question... Is there a trade-off beetween the cut-off frequency of an IIR filter and it's sampling frequency ? In practice I have noticed that we cannot have a relation more than Fs = 100 * Fc with 16 bits coeffcients... Is there a theoritical proof ? Thanks

Started by in comp.dsp13 years ago 7 replies

Hi all, I made a quadrature tone decoder like this : I first sampling the input signal at 300 kS/s from an 8 bit ADC Then I mix this...

Hi all, I made a quadrature tone decoder like this : I first sampling the input signal at 300 kS/s from an 8 bit ADC Then I mix this signal with sine and cosine at the frequency I want to decode (22 kHz) Then I have a decimate filter to sampling at 60 kHz, then I can lowwpass filter at cutoof frequency of 500 Hz with an IIR filter to remove the other tone frequency then I compute the...

## PID controller with second derivative?

Started by in comp.dsp13 years ago 19 replies

Is there any reason to include higher-order derivatives in PID-like control systems? As an exercise for myself, I worked out a...

Is there any reason to include higher-order derivatives in PID-like control systems? As an exercise for myself, I worked out a recurrence relation for O[n] with terms that include the second derivative information of the error signal. Is there any point in doing this? Also, it seems to me that the discrete recurrence relation for a PID process is just an IIR filter over the error signal. Co...

## short term estimate

Started by in comp.dsp13 years ago 4 replies

I could not understand how a low pass IIR filter like below will represent a short term power/energy estimate.. y(i+1)=(1-a)y(i)+...

I could not understand how a low pass IIR filter like below will represent a short term power/energy estimate.. y(i+1)=(1-a)y(i)+ a|y(i)| can anybody tell me anything about this?

## IIR filter - sample instants to flush out existing data

Started by in comp.dsp13 years ago 9 replies

Hi, I have a question on IIR filters. I have an IIR filter running on a TMS DSP. Suppose I have an FIR filter with 'a' taps. If the filter...

Hi, I have a question on IIR filters. I have an IIR filter running on a TMS DSP. Suppose I have an FIR filter with 'a' taps. If the filter is running and I want to flush the existing data at each of the taps out, it would take me 'a' sample instants. Is that correct? Now, if I have an IIR filter with 'a' feedforward and 'b' feedback taps, roughly how many sample instants would it take b...