Linked Questions

-1 votes
1 answer
404 views

Use of FFT to compute frequency response [duplicate]

Is there an algo that uses fft to compute the frequency response of an FIR? Currently I follow the textbook method of evaluating the $z$ transform at $e^{-j\omega}$ for $\omega$ running from $0$ to $\...
Frank's user avatar
  • 11
0 votes
2 answers
37k views

How to plot magnitude and phase response by hand if I have the Transfer Function?

I have the transfer function of the system, which is: $$H(z) = \frac{1-z^{-1}}{5(1+2z^{-1})}$$ How do I sketch the magnitude and phase response? I'm sorry for the bad formatting, it's my first time ...
Othon Lima's user avatar
9 votes
1 answer
7k views

Plotting the magnitude response of a biquad filter

I've put together a multi-band audio EQ using biquad filters. I'm getting the coefficients using the methods from the RBJ cookbook. Now I want to plot the curve showing the magnitude response. I'm ...
MVTC's user avatar
  • 293
0 votes
2 answers
10k views

Plotting the magnitude response of a filter?

I have designed a second order butterworth filter. Sampling frequency: $4\textrm{ kHz}$, Cut-off frequency: $500\textrm{ Hz}$ $$e = \tan⁡\left(\frac{\pi \times f_c}{f_s}\right) = \tan\left(\frac{...
embedded.95's user avatar
5 votes
1 answer
1k views

Fast Integer 8 Hz 2nd Order LP for Microcontroller

I need an 8 Hz 2nd order LP filter. It does not have to be terribly accurate but it should be 2nd order-ish. Performance is much more important. My sample rate at the moment is ~9.5 kHz. The filter ...
squarewav's user avatar
  • 165
3 votes
1 answer
4k views

Difference between $\tt freqz()$ and $\tt plot(abs(fft()))$ in MATLAB

I've plotted the response of a high-pass filter x=[1 -1]; freqz(x) gave me where as the magnitude plot for the ...
phanitej's user avatar
  • 450
1 vote
1 answer
7k views

Amplitude transfer function

Given a LTI-system $$y[n]=x[n]-2x[n-1]+y[n-1]- \frac{8}{9}y[n-2]$$ The transfer function $H(z)$ is: $$H(z) = \frac{1-2z^{-1}}{1-z^{-1}+ \frac{8}{9} z^{-2}} $$ How do I calculate the amplitude ...
yoyoyo jansen's user avatar
3 votes
2 answers
1k views

Why does a higher sampling frequency mess up my bandpass filter?

I was designing a bandpass filter in python using some of the scipy.signal modules. I am plotting the frequency response of my filter to verify that my desired frequency is in the passband. However, ...
kennyvh's user avatar
  • 165
1 vote
1 answer
1k views

IIR Filter Implementation in C results in unstable system response

I need to implement a basic 6th order Butterworth lowpass filter on a DSP that sampled data at 50kHz. I calculate the coefficients using matlab for a filter with the following step response: $$\begin{...
Mantabit's user avatar
  • 121
3 votes
2 answers
1k views

Is there a method to calculate the maximum gain of a biquad?

Given an IIR expressed as a biquad: $$ H(z) = {b_0 + b_1 z^{-1} + b_2 z^{-2} \over 1 + a_1 z^{-1} + a_2 z^{-2}} $$ Is there a way to calculate the maximum gain the biquad attains over the range $0$ ...
keith's user avatar
  • 906
1 vote
1 answer
3k views

Frequency response of a filter - fft vs. freqz

I have designed my filter using firhalfband(N,Fo,A), which gives me the filter coefficients. Then I try to see the frequency response of it. I use these two ...
Lakshmi's user avatar
  • 135
1 vote
1 answer
1k views

IIR low pass filter: floating point and fixed point

I have implemented an IIR low pass filter in direct form 2, the input to the filter is a unit impulse $\delta[n]$. I have calculated the output of the filter for the mentioned input using the ...
sai priya's user avatar
  • 125
0 votes
1 answer
735 views

Phase Response Function / Plotting in Excel (IIR Filter)

Using formula from Audio EQ Cookbook I implemented biquad IIR filters in Excel. I can now plot every transfer function and total of 8 band EQ with shelvings and peakings. My problem is, I can not ...
BugraKezan's user avatar
2 votes
1 answer
697 views

Plot Magnitude from RBJ Biquad

Currently I'm working out plotting biquads in a VST/AU plugin and have problems with the graphics part. I posted in several forums but haven't got a really useful answer for this case. First, tell ...
Chris Ivan Schrago's user avatar
0 votes
1 answer
110 views

Extremely low frequency filters

I have a data acquisition board(A/D+Digital Signal Processor) and I want to check if a digital high-pass filter(implemented in DSP) at an extremely low cut-off frequency(0.05Hz) is actually working. ...
doubleE's user avatar
  • 273

15 30 50 per page