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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Why is this MATLAB butterworth filter giving me wrong results
Given a 128 Hz signal, in MATLAB I entered the following command
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Identify the system from input and output
I am using Excel. If I have an input and an output, and I know that a recursive band-pass filter produced the output, how can I can find the coefficients of that filter?
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A filter in IOS to eliminate a certain frequency range
I am making an application where I record sound on an IOS device using the built-in microphone. I want to process the sound in such a way that only frequencies in the 16-18 kHz range remain; the other ...
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Implementing digital filter by padding with zeros
I am making a 9th order digital bandpass filter with lower and upper corners of 200 kHz and 40 MHz respectively. I am using this filter to filter a 1D time domain signal which is 64k samples long ...
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Multiply filter kernel by sine
1)Suppose that we have low-pass filter with cf equal to 0.1. How frequency response would look like if I multiply filter kernel by sine with frequency say 0.3? How this is related to converting
low-...
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The reasons for filter explosion
Assume signal $x$, sampled at $f_s = 44100\; \mathrm{Hz}$. I tried to filter it using the Butterworth bandpass filter ( $30\; \mathrm{Hz} - 70\; \mathrm{Hz}$) of order $8$. However, as a result I get ...
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Segmenting a frequency series: do we need band-pass filtering?
I am trying to implement what's called the "second spectrum". Basically, you do this:
Take a time series of length $N$.
Divide it into $m$ segment, each of length $N'=N/m$.
For each segment $m$, do a ...
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Design and implementation of causal band-pass filter for biosignals - what to consider? [closed]
I currently work in a project of clinical software (C#) which deals with clinical biosignals, specifically EMG and other low-frequency signals (load-cells, goniometers, and other biomechanical ...
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filtfilt giving unexpected results
I am trying to filter EEG signals using butterworth filter and filtfilt. I have gone through a lot of documentation and these 2 commands seem sufficient for filtering. However, the results are bizarre....
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Filtering method that minimizes ringing in time domain, implementable in Python
I am acquiring data through an oscilloscope, which I am then filtering. I am doing all of this in Python.
I need a bandpass filter with stop bands from 0 to .4MHz, and 4MHz and up. My pass band needs ...
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How do I manually plot the frequency response of a bandpass Butterworth filter in MATLAB without freqz function?
I have code like below that applies a bandpass filter onto a signal. I am quite a noob at DSP and I want to understand what is going on behind the scenes before I proceed.
To do this, I want to know ...
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Filtering the EEG signals
I have very limited knowledge of DSP, so I apologize if my question is trivial :)
I have an EEG signal from which I need to extract different frequency bands. For example, waves in the the frequency ...
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Why is beginning of this FIR filtered signal attenuated?
I apply an FIR filter passing the band around 50/1000 and attenuating the other three frequency components 30/1000, 70/1000 and 110/1000.
Both filters are generated using the Remez algorithm. The ...
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Sampling bandpass signal with spectral replications
I want to clear my thinking on how to approach problems of the type characterized below.
I guess what we want to do is select a sample rate of a sufficient size such that this signal can be fully ...
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Energy in baseband and bandpass signal
Is there any difference in energy content of baseband and bandpass signals? When we see their representation in frequency domain, it looks like a bandpass signal has double the energy content compared ...
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Bandpass Filter window length: filter "in phase" with sinusoidal input
Say you have a bandpass filter and you place it on 40 discretely sampled points from a sinusoid with a period of 40.
Why is the bandpass filter (green curve on the image) only "in phase" with the ...
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Bandpass butterworth filter frequencies in scipy
I'm designing a bandpass filter in scipy following the cookbook. However, if I decrecrease the filtering frequencies too much I end up with garbage at high order filters. What am I doing wrong?
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Separating two sound file frequencies using bandpass filter matlab
can someone please help me? I have a project to implement a superheterodyne transmitter and receiver without using matlab functions that modulate. The first part which I can't seem to get right is the ...
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Using goertzel confuses me
I am having some troubles understanding the algorithm.
My algorithm looks like this.
how come am i able to compute the DFT coefficient using this algoritm.
As far as i know
$$
X[k] = \sum_{i=0}^{...
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How to reverse the effect of analog RC filters on calibration pulse?
I have a low-voltage amplifier with an analog LPF of ~106 Hz and a HPF of 0.482 Hz (both first-order RC). I can choose to apply a calibration pulse that will shut off the input and send a 500uV, 5Hz ...
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Is it possible to implement FIR band pass filter using two FIR band stop filters?
I am trying to filter a signal using a given FIR band stop filter. I have to implement a band pass filter. Assuming I want to get the signal between normalized cutoff frequencies [0.2,0.3] - can I ...
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Bandpass filter on noisy sinusoid that predicts turning points
Is there an application where it is required to predict turning-points of a signal that
is like a sinusoid with constant frequency, variable amplitude and some noise (Gaussian additive noise)? The ...
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Bandpass Filter Implementation in C
I've been googling for a while and came across the audio cookbook and Bjorn's blog explaining it further Link Here.
Background info: I've modified the rtl-sdr open source code to tune to a VOR ...
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what does the statement "band limited signal of 5 KHz" mean
A band limited signal of $5$ kHz is observed at the output node whose sampling frequency is $600$ kHz. What is the minimum order of the filter?
Does it mean:
a signal that is from $0$ to $5$ kHz on ...
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What are filter banks
What are filter banks and what's their application? What's the meaning of $H(z)$ in descriptions of filter banks?
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How to convert a filtered time-domain signal into frequency one? [closed]
I have a signal in matlab like this:
I have designed a band-pass filter in 16-32 MHz range:
and applied the filter to the signal,
the result is like this :
My Question:
what is the easiest way to ...
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Out of memory problem with filter design tool in Matlab [closed]
I have a set of data in excel like this:
column A is time in ns and column B is the electric field strength.
now I want to convert the time-domain signal from these data to a frequency-domain signal ...
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Turn acausal Butterworth output into output of a causal Butterworth without input signal
I have a dataset which contains a large number of time-series which have been filtered with acausal Butterworth filters. For a real-time application, I can only use causally filtered data.
Is it ...
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Filter design for frequencies in range 0-60Mhz
First of all excuse me for asking a seemingly vague question. But i am going nowhere in the problem i am trying to solve.
I am working on a powerline communication system where i need to upconvert ...
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Implementing a phase-neutral band-pass filter using SciPy
Does the following code properly implement a phase-neutral band-pass filter using SciPy?
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Finding audio data in recording
I am trying to find a specific block of data that should hold valid audio data that I want to process. For instance, I record at 44.1kHz, but I only transmit a .5s of content. Since the buffer I store ...
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Multiple filters or not?
I'm processing audio signal sampled at 44.1 kHz. After some other processing, I need to filter the signal between ~5-50 Hz. Achieving this for a signal with such a high sampling frequency appears to ...
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Bandpass filter BPSK
I have a question concerning BPSK and the bandpass filter that seems to be sometimes placed before the receiver circuit (the receiver is a mixer and lowpass filter).
Basically, from what I've noticed,...
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What is the most efficient type of software bandpass filter?
I'm writing a C++ application to extract four modulated carrier signals at four separate frequencies, from a single input signal. I've designed four FIR filters at t-filter.appspot.com but they run ...
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SineWave generation and BandPass filter : Audio
Can any one suggest me a Bandpass filter in java which I would like to apply on generated sine wave of a particular frequency
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Feature Selection by Filtering
so there is this paper I'm reading and trying to understand fully: Towards Practical Identification of HF RFID Devices
http://dl.acm.org/citation.cfm?id=2240276.2240278
I don't want to link the PDF ...
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Calculating a filter's attenuation at a certain frequency from the Q-factor
I'm using the Web Audio API to make a graphic EQ with four BiQuad filters; a highpass, two bandpass and a low pass:
You can see each node representing each filter's frequency. It's working nicely but ...
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Online filter for EEG
My goal is to build a real-time filter for EEG data. The data are being recorded in 512Hz and I wish to filter it (in a real-time, from 0.5Hz to 30Hz in the most optimal way).
Unfortunately I'm not ...
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The transmitted signal of DPSK
I am very confused about how to get the transmit sequence of the DPSK signal.
In my lecture notes, teacher give as the following example.
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What is the ideal FIR length, given a specific pulse length?
I am trying to ascertain what the 'ideal' FIR filter length should be, given the pulse length $T_p$ of a windowed sinusoid in noise that I seek to filter.
As parameters into an FIR filter that I ...
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All-pass filters to remedy group delay
I would like to sum a filterbank made of bandpass butterworth filters to reconstruct an audio signal. Given group delays for each channel shown in the following plot . . .
How would I go about ...
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Is it correct to subtract a low-pass filtered signal from the original signal and use the result as a "high-pass"?
I am having a hard time trying to find documentation to implement band-pass or high-pass filter with python/scipy/numpy.
I can easily create and apply a low-pass filter, though, so I ask:
Would it ...
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Vocoder carrier wave bleed
I made a terrible vocoder earlier and got some help on it here:
My vocoder sounds bad
My new implementation is much better. I'm using the band pass filter described in the document suggested on the ...
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change the frequency component of a spectrum in an audio file
I am working on an audio dynamic range compressor using Matlab.
After calculating the FFT of the audio file, I use several bandpass filters to amplify specific bands separately.
What I want to do then ...
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basic bandpass filter
I am attempting to implement a basic bandpass filter but the center frequency of my filter seems to be irrelevant as I can change it all I want but it has no effect on the filter.
where am I going ...
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What bandpass filter design will yield the shortest impulse response?
Designing a simple 2nd order IIR bandpass Buterworth filter with a centre frequency of 500 Hz and a 1 octave bandwidth gives me the following frequency response ...
Now, if I take the impulse ...
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How can I break a filter down into second order sections?
This is a follow-up question of How do I apply a Chebishev filter? I designed a filter in Scipy:
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How do I apply a Chebishev filter?
I read a paper about a brain-computer interface. In this paper the authors reported "each signal has been filtered with an 8-order band-pass Chebishev Type I filter which cut-off frequencies are 0.1 ...
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Understanding a Bainter Circuit (chebychev filter)
As part of a class in Signal Processing, I am building a 3rd order Chebychev band reject filter. We implement this by using three cascading Bainter circuits. Although not part of the class, I have a ...
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When is aliasing a good thing?
In Hamming's book, The Art of Doing Science and Engineering, he relates the following story:
A group at Naval Postgraduate School was modulating a very high
frequency signal down to where they ...
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