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A band-pass filter is a device that passes frequencies within a certain range and rejects (attenuates) frequencies outside that range.

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How do I begin creating a 31 band equalizer using Matlab?

How to start creating a 31 band equalizer for a real time audio processing system? Given that the center frequencies of each of the 31 bands are the following: 20 Hz, 25 Hz, 31.5 Hz, 40 Hz, 50 Hz, 63 ...
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1answer
22 views

“Side Lobes” When Using a Butterworth filter

So I am attempting to filter a signal containing frequencies at 7Hz, 11Hz, and 74Hz. The signal lasts for 30s and looks like this between -1s and 1s: Using a butterworth filter of order 2 with lowcut=...
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25 views

Notch filter cutoff

I have what I think would be a simple question for a signal processing expert. I have used a notch filter with a cutoff of 100 and 200 Hz using a 4th order butterworth. I am needing to find the ...
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1answer
64 views

Is ideal band pass filter (brick wall filter) linear phase? [duplicate]

I'm very new in digital signal processing. I have multiple sensors and the way I filters the signals in post processing is: take FFT of the signals. put zero on out range of interesting frequency (...
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21 views

DFT or Band pass filter for wristband visualization

I want to work on a little side project to get into signal processing. I want to create a watch-battery powered wristband that visualizes the strengths of the various EM waves at different frequencies ...
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1answer
31 views

Parallel Cascaded FIR Filters

I have a relatively simple question. I know if you connect multiple LTI systems in parallel, overall system's frequency response is the sum of each LTI system's frequency response. Therefore, what ...
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1answer
60 views

In What Way Is the Difference of Gaussian (DoG) More Tunable than the Laplacian of Gaussian (LoG)?

I was reading through this post "What is the difference between Difference of Gaussian, Laplace of Gaussian, and Mexican Hat wavelet?" and noted in Chris Luengo's answer that he mentioned that the ...
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1answer
90 views

Detecting fundamental zero crossing point

I am looking for ideas from the more experienced members on algorithms for determining the fundamental zero crossing point of a 50 or 60 Hz signal. The fundamental zero crossing point is then used as ...
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25 views

How to select Input parameters of FIR band pass filter (narrow band e.g Alpha (8-12 Hz)). A basic question?

I have to filter eeg data (500 samples) offline using a FIR bandpass filter for alpha rhythms (8-12 Hz) providing the fixed order of filter (i-e., 128). Can some one explain what should be the ...
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1answer
49 views

Band limited signals that are sparse

I am looking for examples of signals that are band limited but also sparse. For instance, the spiking of the neurons can be modeled as banded in frequency domain and sparse in time domain. What other ...
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1answer
61 views

What does it take to design a 4th order band-pass filter with -24dB/Octave?

I would like to implement in software the same isolators that the Pioneer EFX-500 features: The manual says the following about the isolators: High-performance 3-band Isolator Function [Fourth-order ...
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2answers
81 views

IQ modulation: baseband to bandpass transformation

can someone explain me these doubts? it is a baseband signal representation. A- complex signal, R- real. If I multiply baseband signal with FT( cos) then the signal will look like this ( on the ...
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1answer
139 views

Bandpass butterworth filter in python is not working

I've implemented this bandpass filter in matlab for the audio signals and it's working as expected. Now, I tried to implement the same thing in Python but it doesn't produced expected results, it just ...
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1answer
44 views

Homodyne concept of receiver

I would like to understand a concept of homodyne architecture of I-Q demodulator and how the wave looks like at each step. It is a bandpass Signal: Step 1: multiplication with cos and sin wave. I ...
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19 views

What means transition band in bandpass filters? [duplicate]

im no a specialist in dsp, but i would like to know what means a transition band in band-pass filters, in this statement: ...
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38 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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1answer
177 views

How to plot the poles and zeros of this Bandpass Filter in MATLAB?

So I'm trying to design a band pass filter in MATLAB (with a center frequency of 10kHz and a sampling frequency of 44kHz). I have calculated the transfer function but I'm not sure how to enter this ...
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1answer
57 views

How does works a bandpass filter?

My question is about the action of a bandpass filter. First, I have a temporal signal. I convert it in a spectral signal via a FFT. Now, I want to apply a bandpass filter on that spectral signal. But ...
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18 views

Can you use the theory of Signal Space to study Band Base digital systems?

Introduction: There is one way to study different modulations in band pass digital systems and is working with "signal space" and the Constellation Diagram. My questions about this are: 1) Is it ...
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2answers
50 views

Bandpass overshoots at the beginning and end of signal: why?

The picture below shows the original data in the upper figure and the filtered data in the figure below. The filter applied to the original data is a simple bandpass implementation: $H(z) = \frac{0....
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3answers
85 views

No-lag causal bandpass filter kernel formula

Can anyone point me towards a formula for a good (for any values of "good") no-lag causal bandpass filter? I am doing sound processing and I need to identify starting points of certain sounds (target ...
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2answers
67 views

Matlab 'filter' returns negative values (when filtering a positive signal)

I just filtered a only positive signal with the following filter which is a bandpass filter with the following characteristics: ...
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1answer
40 views

Remove Frequency Range

I got a signal and I would like to remove a specific frequency range. I am a frequency noob, so I will explain it by images: I have a frequency filter (butter bandpass): I have a signal and it's ...
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258 views

All pass filter design for group delay compensation

I've designed an IIR bandpass elliptic filter in Scilab with the following parameters. Sampling Frequency = 25000 Hz Lower cutoff frequency = 100 Hz Upper cutoff frequency = 150 Hz Pass band ripple = ...
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139 views

IIR filter group delay

I've designed an IIR bandpass elliptic filter in Scilab with the following parameters. Sampling Frequency = 25000 Hz Lower cutoff frequency = 100 Hz Upper cutoff frequency = 150 Hz Pass band ...
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1answer
30 views

When applying a bandpass filter designed in Matlab's DSP system toolbox, is it necessary to do any normalization?

I'm applying the next bandpass filter to the data of an impulse response coming from .wav; it fades data below 10 Hz and above 400 Hz: ...
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1answer
98 views

Band energy and Parseval theorem

In Python, I consider a dummy signal as follows: fs = 512 sig = np.random.standard_normal((fs,)) sig corresponds to 1s of ...
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80 views

Why does bandpass performance break down at low frequencies? [duplicate]

I've got a basic bandpass filter design that works great at higher frequencies, but breaks down at around 150 Hz. Here's the MATLAB code: ...
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58 views

Simple Pole-Zero placement bandpass filter doesn't work in MATLAB

I'm trying to make a simple bandpass filter using Pole-Zero Placement method, which has unity gain at frequency w=0.37pi and 3 dB cutoff frequency wc=0.42pi (has a gain of 1/sqrt(2) at that frequency)....
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2answers
795 views

How do I calculate the impulse response of an ideal band-pass filter?

I understand the FR of an ideal BPF is just 1 between the two cutoff frequencies and 0 everywhere else above and below them both. But with arbitrary cutoffs, how would one find the IR of this ideal ...
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17 views

Minimum value of the transition band gap

This question is from the book Discrete Time Signal Processing by Oppenheim and Schafer (3rd ed). I was going through the problems in the chapter concerned with filter design, and stumbled upon this ...
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2answers
229 views

Help with audio EQ cookbook BPF filters and Q

I am fairly new DSP, and am using maths that I have not used in 20-30 years. I have been working with Cookbook formulae for audio EQ biquad filter coefficients by Robert Bristow-Johnson and am having ...
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1answer
131 views

Second order section digital Bandpass

Does anyone have a ressouce on how I can calculate second order section bandpass coefficients? What I tried allready: I used following formulas from the Book Electronic Circuits (U.Tietze, Ch. ...
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2answers
123 views

Bandpass filtering IQ samples from USRP

I have an USRP (B205mini) with an RX frequency of 900 MHz and a bandwidth of 100 MHz. I want to distinguish between two raw, unmodulated signals at respectively 875 and 925 MHz. My approach would be ...
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66 views

Trouble in applying bandpass filter on BPSK signal

I'm trying to make BPSK simulator using Python. After I made signal communication without adding bandpass filter which I succeeded to decode on my receiver, I added bandpass filter in Tx/Rx to clear ...
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90 views

Avoid side-lobes from bandpass filtering? (Synthetic data)

I am implementing data-filtering in Python using Scipy package, over synthetic data. Filter design: scipy.signal.butter Filter implementation: scipy.signal.filtfilt The signal is made up of ...
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2answers
523 views

Matlab `filtfilt` provides excessive transient

I observed that filtfilt suffers from an undesired behavior when I provide IIR bandpass filters having steep transition bands. Specifically, the output signal exhibits excessive transient response; ...
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51 views

Standard Method for Multiband Compression

I am looking into designing a multi-band audio compressor program and was wondering if anyone can explain how such programs go about separating and processing the different frequency bands. The way ...
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1answer
167 views

DWT versus band-pass filter

Which technique gives better result in extracting a band from a signal, let's say the alpha band (8-13 Hz): using a band-pass-filter or a DWT (Discrete Wavelet Transformation)? P.S.: I am working in ...
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102 views

What is the power spectral density after filtering?

Consider a signal $x(t)$, which is input to a pulse shaping filter with transfer function $g_t(t)$: $$x(t) = \sum_n d_n \delta(t-nT_s)$$ with $n$ an index from negative to positive infinity and $...
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3answers
161 views

Audio wave amplitude decreased after FIR filter

I am doing sampling and filtering for a 17KHz sine audio wave signal, the Nyquist frequency is about 20.8889KHz. I found the fact that this audio signal's amplitude decreased dramatically after it ...
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140 views

Envelope frequency in band-pass filter?

I have a respiratory signal that I filter with two different bandpass filters. The signal lies at about 0.2Hz. The first bandpass goes from [0.05,0.7]Hz (left image). I calculate the approximate ...
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1answer
70 views

Mel seperated filter banks

I am currently a bit confused. I am currently trying to understand the MFCC extraction process, and don't understand how the Mel filterbanks only provide a scalar output from each filter bank. What ...
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1answer
36 views

Audio signal series' beginning points(about 50) distort after a bandpass filter

I am using some bandpass filters to detect a certain freq of the sampled audio series in noisy environment. Everything is OK except this: I found that for many bandpass filters I tried(butterworth, ...
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2answers
91 views

How to filter out everything but a single frequency in the time domain?

I'm new to signal processing and would like some insights about the best way to filter simple data without being too computationally intensive. I have an audio signal and I want to extract a single ...
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1answer
287 views

FIR filter Gain of 0dB at Passband Frequency

I have designed a FIR pass band filter. The impulse response looks good and on applying this on my input data, the filter works as desired. Now I have a requirement in my system to have exact $0$ dB ...
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1answer
235 views

Bandpass fundamental and harmonics in Matlab

I have a signal in time domain whose sample frequency is Fs=25600. I would like to remove from the fundamental F=285Hz and all its harmonics (2*F,3*F,etc). I tried to use the comb filter in Matlab ...
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1answer
663 views

Design narrow bandpass filter for signal with high sampling rate

I have to bandpass-filter a signal which has been sampled with 4000 Hz. Only frequencies around 15 Hz shall remain after filtering (let's say in a band between 10 Hz and 20 Hz; the narrower the ...
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2answers
2k views

Bandpass filters with python for low frequencies

I have a signal, sampled at 1 kHz, that I would like to analyze in third octave bands. For that purpose I defined Butterworth filters with proportional bandwidth. This works well for higher ...
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1answer
807 views

How to implement bandpass filter on complex valued signal?

I am using Scipy to implement bandpass filter but it assumes that positive normalized frequency is passed but I & Q samples range from [Fc-Fs/2,Fc+Fs/2] where Fs is sampling frequency & Fc is ...