Questions tagged [highpass-filter]

A high-pass filter is a device that passes high frequencies and attenuates frequencies lower than its cutoff frequency.

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Linear phase Kaiser filter

I need to remove some low-frequency components in my audio using Linear phase Kaiser filter with beta 0, 5, and n = 2400 and a cutoff frequency of 15Hz. I need Python or Matlab code to implement the ...
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47 views

Are high pass/low pass filters FIR filters?

I am trying to understand the basic categories of DSP filters, and it seems that the two main groups are FIR and IIR, however I'm not sure how to categorize high pass, low pass, band pass, and band ...
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63 views

Highpass filter square wave

Generated a 1kHz square wave in Audacity and normalized it to 0dB (fs = 44100Hz): Added a 24dB/oct high pass filter (std Audacity plug-in), cutoff frequency set to 100Hz. Result: Zoomed version: ...
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3 dB cut-off frequency of first-order IIR high-pass filter

As descipbed in this great answer (thank you Matt L.), the suggested exact formula was very precise. I need a first order high-pass with similar precision. EDIT: (clarification) The low-pass filter ...
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81 views

Calculating the 3dB frequency of an nth order low pass filter and nth order high pass filter

I am using the 6th order high pass filter in the C code. And the cut-off frequency selected for it is 150 Hz and the sampling frequency being used is 32000Hz. Now, I want to calculate the 3 dB ...
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Correct way to build a basic filter bank (ie. for simple multiband audio processing)?

I need to build a filter bank for multiband processing. Last time I tried I was just starting at coding/DSP so I failed and didn't get a flat spectrum out of it. I just want to know the basic ...
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69 views

Ideal high pass filter for discrete signal

there. I currently get stuck on a question. I was asking to find an inverse discrete-time Fourier transform for the ideal high pass filter. Here is the question It is getting more confused after I ...
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Adjusting coefficients of a LP and HP filter for a new sampling rate

I am pretty new to DSP and try to undertand some concepts and the relations between them. I currently learning about the Pan-Tompkins algorithm and trying to recreate it in Matlab (Pan–Tompkins ...
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Correct signal analysis flow (Wind Turbine vibration)?

I have vibration data from WT (gearbox) sampled at 25.6 kHz. From a previous post I received a lot of good recommendation. What I am trying to do: Find early stage bearing faults by using an ...
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80 views

FIR Filter - Low Pass Filter coefficients to High Pass filter coefficients

I need to convert this 12 Tap Low Pass Filter to a High Pass Filter. The coefficients of the Low Pass Filter are as follows: ...
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103 views

Envelope analyis basic question

I have a vibration signal sampled at 25.6 kHz, and I want to perform Envelope Analysis on it. "Vibration-Based Condition Monitoring of Wind Turbines" by T. Barszcz has the following figure: I ...
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Need help with removing low frequencies

I have a signal in which I want to remove low frequencies with high pass filter. The sampling frequency is 12.5Hz. The signal around 0.5-2Hz. I'm using the following parameters for my filter: ...
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New magnitude frequency after apply highpass butterworth filter

I want to use high pass filter to filter frequency less than 100Hz. I use this code in python. ...
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FFT response for noisy signal, averaging the response and

I try to analyze a system's state with acceleration sensors by measuring the frequencies and amplitudes. Since a cheap sensor is used, I have a noisy signal in the beginning (up to 40Hz - see below). ...
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Why is my signal attenuated after applying a HighPass-filter?

I am new to DSP, but I've been attempting apply a butterworth high-pass filter on a 1D array (Values peeking at 300~) to eliminate any noise, yet when applying a high pass filter, I'm ending up with ...
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93 views

Applying a 2D band pass filter (Butterworth ?) to an array with NaNs

I am trying to filter out the low frequencies of an array looking like this : For now, I am taking transects of this array and applying a 1D - butterworth band pass filter : ...
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How to visualize high-pass filtered images?

When I try visualizing a high-pass filtered image, all I see is gray, similar to the middle subfigure in the attached figure from a related paper. The authors claim they normalize the image to have ...
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Check work: Expression for 3dB bandwidth for frequency response of high - pass filter having just one pole

The input output relationship is given: $y[n]=ay[n-1]+bx[n]$ $-1<a<0$ I applied z-transform to get the transfer function : $$H(z)=\frac{b}{1-az^{-1}}$$ Since $-1<a<0$, the maximum ...
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Biquad high-pass filter not working as expected

I'm trying to implement a high-pass filter using the the coefficients described in RBJ's well-known EQ cookbook (see https://www.w3.org/2011/audio/audio-eq-cookbook.html). However, when I run white ...
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57 views

Attenuate the low frequencies in a speech wave

I am designing an FIR filter to attenuate the frequencies below 300Hz. I designed the filter using the ...
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512 views

Poles and zeros map, High pass filter

Given the following poles and zeros map I have to identify qualitatively, which filter type is represented (Low-Pass, High-Pass, ...). In the solution it says, that this is a high pass filter. ...
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1answer
103 views

What impact have different types of border-handling on high pass or low pass filtering?

When high or low pass filters are being applied to an (grayscale) image, the borders need to be handled separately. They could be filled with 0's or 255's (b/w), repeat the nearest pixel value, or ...
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73 views

FIR filter not eliminating out of band noise?

I have a simple FIR filter that should eliminate all lower frequencies: ...
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Determine filter type using recurrence relation

Given the recurrence relation: $y[n] = x[n] + 0.5y[n-1]$ I want to determine the filter type (i.e. LPF, HPF etc.) I try to use Z transform, and get that the the transfer function is $H(z) = \frac{2z}{...
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Is the Sobel filter a high pass filter, and if not, what is the difference between them?

I am an artist with an interest in signal processing. I realize that maybe this question very basic, but the web banner on the frontpage says "anyone can ask", so I assume that means beginners too. ...
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67 views

Why do cutoff frequencies of a high-pass digital filter differ from the ones i used to transform it from a low-pass analog filter in MATLAB?

I need to transform an elliptic analog low-pass filter to a digital high-pass filter but i'm having a problem because the resulting filter has lower cutoff frequencies than the ones i set. Here is the ...
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407 views

Are there DC removal techniques that do not introduce a filtering transient?

I have an application in which I need to remove DC components from a sampled signal in real time (basically the same constraints of ECG, but it has nothing to do with the brain). My measured signal in ...
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3answers
1k views

How to Classify Image Filter as Low Pass Filter (LPF) or High Pass Filter (HPF)?

I am currently reading on the topics of image filtering and convolution kernels. While the process of convolution is clear to me, I do not understand, how one arrives at the statement, that a certain ...
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524 views

Background Noise Reduction in Audio signal

I using high pass filter for reduction or removal of noise of audio signal but still some noise is there in signal.i have MIC,Head Set,Bluetooth and phone are connected to controller,while talking on ...
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466 views

How to understand the relationship between the filter time constant and the half-power cutoff frequency

I learned that the time constant can be computed as $\frac{1}{2 \pi f_0}$, where $f_0$ is the half-power cutoff frequency of a high-pass filter. However, I was wondering how the time constant and the ...
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794 views

Poles and zeros map

Given the following map of poles and zeros for some $H^L(s)$: How can I understand from the map that the given Transfer function is LPF? Hence the poles are located at the hight frequencies it should ...
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159 views

High / Low Pass Filters from Zero

I everyone, I'm a computer scientist but not from the signal processing community. I want to implement a real time digital low pass filter (to begin with) for a sound processing application. I've ...
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102 views

How to combine filters' effects?

My question is about the use of many filters on a sound signal. I found the following transfer functions for the high cut, the low cut and the pass band filter : H = K / (1 - x^2 + j.x/Q) H = K / (1 -...
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253 views

Are there any quick way to tell if a kernel is a high-pass filter?

Im new in this image processing field so please be gentle with terminology, i have a kernel of 3x3 and i want some way in order to test if its a high pass filter or not Thanks in advance
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How to Classify a Kernel as Low Pass Filter (LPF) or High Pass Filter (HPF)? How to Transform an LPF Kernel into HPF Kernel?

The filter impulse response is [1/9 1/9 1/9;1/9 1/9 1/9;1/9 1/9 1/9]. how do i determine whether it is an Low pass filter or a high pass filter. If this is a low pass filter how do i convert it to a ...
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153 views

temporal high-pass filtering to approximate phase derivative

I am currently following the algorithm as based on a previously published research article "A Motion Detection Algorithm Using Local Phase Information" by Lazar et al. The basic overview of the ...
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700 views

Which FIR filter window to choose?

I need to design a high pass FIR filter based on parameters given. However I'm stuck at which window i should select. How do I calculate the parameter M? The guide I referred myself to was behind ...
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2k views

Designing high-pass filters using impulse invariance

One of the main disadvantages of realizing digital filters using impulse invariance is aliasing. According to the Nyquist sampling criterion, in order for the frequency response of the digital filter ...
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936 views

How to apply Butterworth High Pass Filter [closed]

I have a problem with applying Butterworth High Pass Filter to my data. I would like to print filter for Bx and By matrix. As ...
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1k views

How to Design a Pre-emphasis filter knowing the gain, a zero and a pole?

I am simulating an FM radio signal in order to use it as a waveform in passive radar; for this purpose I'm following an article: Analysis and Emulation of FM Radio Signals for Passive Radar In a ...
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95 views

Modulation and filtering

When I modulate a signal $x(t)$ with $\cos(2 \pi f t)$ and the modulated signal passes through a HPF, what output do i get in the frequency domain?
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799 views

Real-time FIR filtering on time domain

My previous question wasn't clear. So I thought it'll be good idea to repost with more details. I've designed a 100th order windowed highpass FIR filter with 3Hz cutoff frequency for my ADC datas ...
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216 views

Butterworth high pass filter

My signal's base line is around 1. When I apply Butterworth high pass filter with cut off frequency Fc = 2Hz signal's base line drops to 0. My data are from the accelerometer. Is this behavior normal ?...
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381 views

Why did a digital HPF increase the gain of high-frequency signal?

Background: I was trying to remove the DC component of a load cell signal using a high-pass filter. I don't care about that anymore. I'm curious why a digital filter and an analog filter behave ...
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Filter design - Rules of thumb regarding ratio of sampling and stop/pass frequency

The issue: I have a signal in the time domain sampled at 51.2KHz. I want to apply a highpass filter with a pass frequency of 20 Hz. The problem: Using Matlab to do that, the design of the filter ...
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266 views

How to get output from High Pass filter on this signal?

I'm trying to solve this exercise: Consider a High-Pass filter with a cutoff frequency of $W=2\pi$ Calculate the output signal if the input signal is $x(t)=\displaystyle \frac{\sin(4\pi t)}{\...
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Forward Backward filter Scipy - $\tt signal.filtfilt$ changes the amplitude when $\tt signal.butter$ is used with $\tt btype='high'$

In the plot below the blue wave is the original signal. The orange wave is after the low pass filter. The green wave is after the high pass filter. I have a noisy ECG signal stored in the ...
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2k views

highpass filter design in Matlab

I hope to design 1st order highpass filter from transfer function. In the example of 1st order lowpass filter, I first get the coefficients of numerator and denominator in the variable 'b' and 'a'. In ...
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384 views

Determine filter type (HPF or LPF) by its coefficients

I want to determine optimal initial states for a FIR/IIR filter to get rid of oscillations and shifts at the initial interval. I've found that these initial states depend on filter type in the ...
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1answer
13k views

High-pass filter in Python (Scipy)

This code is taken from a pitch detection algorithm. It is called before pitch detection to remove low-frequency noises. ...