# Questions tagged [bandpass]

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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### About the process to convert basedband signal into passband

Theoretically, the passband $y(t)$ signal equivalent into baseband signal $x(t)$ is given by: $y(t) = \Re \begin{bmatrix} x(t) e^{(-i2 \pi f_ct )} \end{bmatrix}$ where $\Re$ represents the real part. ...
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### How to generate wideband Gaussian white noise

I want to generate correlated complex white Gaussian noise signals in MATLAB. What I do is that I take complex Gaussian random variables with unit-variance and multiply them with the desired input ...
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### How can to obtain the hughcut, lowcut and bode constant of a bandpass digital filter?

I need to create a bandpass filter amplifier in python; and determine the transfer function, graph the bode diagram, and print the highcut frequency, lowcut frequency, the bode constant and the ...
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### How can to obtain the transfer function of a bandpass digital filter? [duplicate]

I've been asked to: create a bandpass filter amplifier in python, determine the transfer function, graph the bode diagram, and print the highcut frequency, lowcut frequency, the bode constant and the ...
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### Find a band-pass filter

The question is: how can I define $h_1[n]$ in such a way that $h [ n ] = \delta [n - 1 ] + 2 \delta [n -2 ] + h_ 1 [n]$ is a band-pass filter. My thought was the following. Firstable, I wrote the $Z$-...
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### SOS-matrices' order does not correspond to given parameter when designing bandpass with scipy.signal.butter

I do not understand why this scipy operation: ...
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### Basic question about Bandpass and lowpass filter using Python

I have a signal that is the sum of 3 signals that has just passed through a transmission channel. I need to put filters to this signal (bandpass and lowpass) and then apply demodulation and get one of ...
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### Theory behind the matlab butter function with the parameters n and [Wl, Wh]

I am writing the theoretical background in my thesis but my thesis is more centered on deep learning and the signals that I am using for classification were filtered through the ...
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### BPF Filtering with DSP IIR Realtime C++ filter library

I am working with complex samples, I have a main signal at 630KHz, my Fs is 1.26MHz and BW is 12.6KHz. If I plot a frequency-magntitude spectrum it looks like this: As you can see along with my main ...
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### Find the output signal in a Low Pass Filter for a given cutoff frequency range

I have a scenario where 𝑥(𝑡)=2⋅sin150𝜋t +sin250𝜋t and g(t)=𝑥(𝑡)sin250𝜋 . The signal g(t) is passed as input through an ideal lowpass filter with cutoff frequency(fc)= 300𝜋 and passband gain= 3....
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### Find the band pass signal for a given low pass range and cutoff frequency?

We know the fact that a bandpass signal is defined for real values. But for a typical scenario where we have a signal in the lowpass range:say : 𝑥𝐿(𝑡)=𝑗𝑋0 sinc(Bt) and the transformation of the ...
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### How to combine highpass and lowpass filter to implement a bandpass filter

I want to implement a bandpass filter by using and combining my highpass and lowpass filter functions in Python: ...
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### How to create a real bandpass filter?

I'm trying to create a real bandpass filter (17-point) in Python by calculating the coefficients b of a signal. This is the formula I'm using: $$b = \cos(ω(k-k_m))$$ for $k = 0,1,..,L-1$, where $k_m$ ...
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### implement bandpass filter on complex valued signal? (C++)

I want to filter out complex valued samples - Bandpass filter. I have 100 complex samples and I wish to filter out a range of frequencies from it, as you can see in the result of the FFT, there are 3 ...
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### Step response of bandpass fitler

I'm working on a virtual bass system and the signal flow is as follows Where NLD denotes the nonlinear device which introduces both odd and even harmonics, and z^-D is to compensate the group delay ...
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### How to get the difference equation from impulse response?

I'm trying to solve a problem about filter design. We want to design a equalizer filter which have the following frequency response : How can i get the difference equation from the impulse responce ...
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### Why use a notch filter to implement a bandpass

I have seen in a few papers, for instance in this one, the following method : Find an initial "frequency of interest" (FOI) Filter the input signal with a Notch filter around the FOI ...
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### Passband filter with 0.3 to 0.9 Hz passband on signal filtered at 100 Hz

I have a signal sampled at 100 Hz with the frequency spectrum seen below. What I would like to do is to filter out the region around 0.7 Hz (say 0.7 ± 0.3 Hz) (leftmost red circle) and get rid of ...
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### How to properly band-pass filter an autocorrelated signal?

Let's consider an example ECG time series, sampled at 360Hz: I verified that autocorrelating a signal preserves its frequency content. For instance, both original and autocorrelated data show the ...
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### Narrowest passband dsp filter one can apply

I was wondering how one would know the narrowest pass-band digital filter one can apply, given the original signal's sampling frequency. For example on a signal coming out from a 14 bit ADC acquiring ...
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### Paper replication: Validating the proper way to pass .wav audio breathing data through a bandpass filter

I am working on trying to apply a low and high pass filter to an audio file that contains a set of exhalations over a microphone. The inhalations have been cut out of the file, and the exhalations are ...
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### FIR filtering returns "static" signal

//PROBLEM I'm trying to filter EEG trials from an array in which each trail has dimensions [8x125] = [number of channels x samples@250Hz], but the resulting signal looks static and wrong. Why is this ...
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### Is it possibel to use CNN to bandpass signal?

I have a time serie dataset and want to train a CNN-LSTM model to predict as well as detect outliers. How can I use CNN to filter the signal and extract features from specific frequency band?
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### How to identify from poles and zeros if it is a bandpass

For an example, this is a figure I made from MATLAB, based on the poles and zeros, how can identify if it is a bandpass filter.
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### Meaning of term in notch filter coefficient

I have a discrete implementation of a notch/bandstop filter that allows me to specify the stop band frequency, the width of the notch and the attenuation of the stop band frequency. I've been tasked ...
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### Bandpass filter equivalent for amplitude

I have a signal where I am using a bandpass filter to limit the frequency range. I am also interested in filtering the remaining frequencies (after bandpass filtering) within the signal by their ...
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### How Short-time Fourier transform (STFT) is different from from filtering?

If we want to know frequencies in a signal over time I know we can use Short-time Fourier transform (STFT). but I read in a paper "The spectrogram representation was obtained by first filtering ...
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### Problem wih (diverging?) digital IIR filter for an online acquisition system

I am trying to plot windows of acquired data from an LSL-compatible system. For the example below, let's consider 1-second window of a 64 channel EEG system. In practice, I use shorter 0.2-window, but ...
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### ANSI S1.11.2004 Octave-Band Filter implementation

I am trying to implement some code to firstly generate an Octave-Band and Fractional-Octave Band filter. I have used MATLAB's octaveFilter method to generate compliant Class-1 and Class-0, 1/1 and 1/...
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### Filter odd or even harmonics with notch or inverse notch filter

Hi i had the following question. I have a signal containing a 200Hz sine wave and it's odd and even harmonics (no other frequencys or disturbing signals are contained). What i'm looking for is a kind ...
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### Why must the order of a Band-Pass and Notch filter always be even?

My professor mentioned that the order of a band-pass and a notch filter must always be even, when showing an example of designing a digital filter using the bilinear transformation. Then he also ...
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### power spectrum of passband of ofdm is it right shape or not?

I tried to get power spectrum of ofdm passband signal. Below is the whole matlab code for that with BPSK+ofdm. and I got the power spectrum as below. I wonder that is that right form or not? ...
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### How to find Cutoff frequencies (f1 &f2) for a narrow band pass filter for a particular central frequency?

This is a basic filter question I think. I want to define a narrow bandpass filter's cutoff frequencies (f1 & f2) for a particular central frequency (fc) in iir filter I think in this case ...
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### How to calculate SNR variation with period?

I want to calculate the SNR variation of a signal with respect to the period. The current technique I am using is calculating SNR iteratively by applying narrow bandpass filters of different range, ...
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### Bandpass filter vs sequential high and lowpass filter in Matlab: weird difference

I am trying to bandpass a neural signal acquired at 20kHz between 0.5 and 100 Hz. I have tried to do it in two ways. The first way is to sequentially highpass and lowpass the signal and the second one ...
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### Does my filter desing for unusual EEG experiment looks good?

I have made some progress since my last question, and again I am asking you for advice. Hi, I'm still designing an unusual (in terms of signal analysis) EEG experiment, which forces me to design my ...
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### Is there an adjective describing a filter with kernel that has zero mean?

A linear filter with a kernel that has zero mean could be thought of as a "DC-rejecting" filter. Is there a better or more commonly used adjective for such a filter?
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### Filter recognition from transfer function

I have a filter with this transfer function in the z-plane $H(z)= z^{-k}$. Which type of filter is this (BP,LP,BS)and why? I have a delay filter with zero/poles equal to zero and the magnitude ...
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### filtering difference b/w freq and time domain

When you want to get the specific frequency (ex. around 1000Hz), you might take FFT, remain the frequency you want, and reduce the power of the other frequencies you do not. ex.) if fs=16khz and ...
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### Filtering sidelobes

Good evening to everyone, my question is probably trivial, but I'm new to DSP. I have a tone at the frequency 0.5 Hz, amplitude 0.001 V, and with a big DC component of 0.5 V. This signal is sampled at ...
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### Derivation of the lowpass to bandpass transformation

I have a basic question. The "well known" lowpass to bandpass transformation is $$s \longmapsto \frac{\bar{s}^2 + \omega_1\omega_2}{\bar{s}(\omega_1 - \omega_2)},$$ which gives a bandpass ...
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### Why is there a dip in this Chebyshev filter response?

I want to build and simulate a 6 GHz, 4th order lumped-element Chebyshev bandpass filter with a maximum passband ripple of 0.1 dB and a bandwidth of 1 GHz, and as I understand it, there should be 3 ...
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### EEGLab import .mat file

I am new to EEG and signal processing, anyone can please check if I fill in the right numbers? I am confused about those terms. For example, the recording using 22 EEG channels and 3 EOG channels, ...
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### How to filter a signal using a bandpass filter consisted of two moving average filters?

I want to filter a PPG signal on a microcontroller. I have limited memory and a was searching for low computational methods. I found the work of Kazuhiro Taniguchi, Earable POCER: Development of a ...
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### Butterworth filter of the acceleration and drifting displacement problem

I am only mechanic engineering and I need to filter my acceleration from MEMS mobile phone which has a noise and drifts. Here is my data. Acceleration vs time from an app mobile phone ...
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### Bandwidth of a bandpass signal

If the Fourier transform of an aperiodic continuous time signal has signal components between the minimum frequency w1 and the maximum frequency w2, but not all the frequencies between w1 and w2, is ...
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### Cosine modulated impulse response

How do we show $y_0(n) = y_1(n)$ when $h_k[n] = h[n] \cos(\frac{2\pi}{L} k n )$
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### IIR filter relationship between number of poles, order and second order sections

I have ported Iowa Hills Code Kit to a mcu to calculate IIR filter coefficients. They are used to initialize the CMSIS Biquad Cascade IIR Filters Using a Direct Form II Transposed Structure. Trying to ...
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As I know, the transmitted pass-band signal whose carrier frequency is $f_c$ can be written as follow: $s_1(t) = \text{Re}(a(t)e^{j2πf_ct})$ , where $a(t)$ is the complex modulated base-band signal. ...