Questions tagged [bandpass]

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

Filter by
Sorted by
Tagged with
1
vote
1answer
47 views

Plotting curved peaks on PSD graph

I am a PhD student with little engineering experience, currently attempting to recreate the signal processing techniques used in this paper: Monitoring Vital Signs and Postures During Sleep Using WiFi ...
0
votes
0answers
36 views

FIR bandpass filter for complex baseband signals

I am DSP newbie and I need to apply a bandpass filter to the complex baseband signals of bandwidth 20MHz and sampling rate 61.44 MHz. Below is the octave code for the same and I have obtained ...
0
votes
1answer
15 views

Generating spectrogram for band-pass filtered wav file python

I have some .wav files of heart sounds. I want to apply band-pass filter [20Hx 100 Hz]. Then generating PCG images size of 560x420 pixels and RGB format. How could i do this? Any help will be highly ...
0
votes
1answer
77 views

what is the theory behind Butter function?

I want to understand why this code used tan and cos ? ...
2
votes
3answers
79 views

Matlab IIR cheby2 bandpass, problems with Magnitude

I am trying to implement an IIR bandpass in Matlab. There are two things I don't understand. But first of all, let me post the code. ...
0
votes
0answers
16 views

What is wrong with band passing by inverse Fourier transforming a section of a signal's frequency spectrum? [duplicate]

If the question is unclear, here is what I mean in Python using scipy.fftpack: ifft(fft(arr)[x:y], len(arr)) What is wrong with this method of band passing?
1
vote
2answers
94 views

Old style signal processing?

I am wondering if "an array of overlapping band-pass filters" it is 'mostly' equivalent to a Short-Time Fourier transform. See this (figure down), where $s(t)$ is the signal; LPF a second-order low-...
2
votes
2answers
184 views

Numerically Stable IIR filter

I am making an IIR Filter and I am running into problems with stability with higher orders. The values go off to infinity as soon as it starts. So far, I've been using MATLAB to generate my filters ...
0
votes
1answer
63 views

Manually creating a lowpass filter from the frequency domain: what phase?

In an attempt to gain a better understanding of DSP, I want to create a very simple (1D) lowpass, or I think more correctly "stop-band" or "band-reject" filter, to filter out a single frequency, e.g., ...
0
votes
2answers
70 views

White noise and its phase after narrowband bandpass filtering

Suppose $w(t)$ is a white noise with uniform spectral density $N_0/2$. It is bandpass filtered to get a narrowband white noise $n(t)$ for $f_c - B_T/2 \leqslant |f| \leqslant f_c + B_T/2$. We write ...
0
votes
0answers
19 views

Why do I need this modulo tweak to bandpass filter an I/Q signal

I have an I/Q signal with $f_c=2.06\text{MHz}$ and $f_s=50\text{KHz}$. I am looking the first 256 samples of the signal, which is a NumPY array of complex numbers. If I do a spectrogram of this ...
0
votes
0answers
32 views

How to design a bandpass FIR filter?

I want to design a bandpass filter (BPF) using a FIR filter by the window method. I have $f_{c1} = 3\, \mathrm{kHz}$, $f_{c2} = 6\, \mathrm{kHz}$ and slope is $-80\, \mathrm{dB/dec}$. How can I find ...
0
votes
1answer
79 views

Bandpass filter with very high sampling rate

Consider a bandpass filter with Low Cut 17Hz, High Cut 22 Hz, Fs = 45000 Hz and Order = 6. When I pass a mixture of multiple sinusoidal waves through this filter (with a sine wave of frequency 20 Hz), ...
1
vote
1answer
66 views

Bandwidth of a finite impulse response filter

In a machine learning application, a model learns to apply a filter h(n) via convolution to a 1-dimensional input signal s(n) (e....
1
vote
2answers
58 views

Filtering Surge Signals

I am working on a matlab program which needs me to detect the pattern of surges in a signal and then remove them. I tried out various filters like median, hampel, butterworth etc. but couldn't get an ...
0
votes
0answers
23 views

Causal bandpass using fft?

I would like to take a time series of several spikes or narrow Gaussians and bandpass using an ift/ifft together with a frequency domain mask to create a series containing band-limited spikes. This is ...
1
vote
1answer
63 views

Why is Cheby 2 filter uncommon?

I've been reading the Chebyshev filters chapter in The Scientist and Engineer's Guide to Digital Signal Processing and it says "The Chebyshev filters discussed in this chapter are called type 1 ...
0
votes
0answers
21 views

How to get the amplitude output of a single frequency from a Resonant Bandpass? (ie. Using a reso BP as an envelope…)

A resonant bandpass like this: is resonating at a frequency of 125 Hz. You are controlling the decay time by modulating $Q$ accordingly. The BP is being excited by a MIDI triggered impulse. At its ...
0
votes
0answers
19 views

Periodic non-uniform sampling - effective bandwidth to select correct anti-aliasing filter

What is the effective bandwidth of sampling at a rate $f_s$ for a burst of $N$ samples, where the bursts are triggered at rate $f_B$? For example, say $f_s \approx$ 10 kHz, $N \approx$ 1000 and $f_B \...
0
votes
2answers
61 views

Valid approach to implementing a band pass filter

Suppose I want to perform Spectral shaping on a signal, i.e, modify the gains in a band of frequencies. Would there be any difference if I do that using the following two methods? - Use a band pass ...
0
votes
1answer
36 views

How does the power spectrum of the amplitude envelope depend on its underlying carrier frequency?

when looking at the amplitude envelope of an oscillation (see red trace in Figure below), it seems to me as if the frequency content of the envelope depends on the the frequency of the underlying ...
5
votes
2answers
179 views

How to determine if a filter is bandpass/stopband from its pole-zero diagram in z-domain

How can we determine if a filter is bandpass or stopband, just by looking at its pole-zero diagram in z-domain? For exmaple, if we have a system with third-order pole at the origin and a zero on the ...
0
votes
1answer
362 views

Third octave bandpass filter with python

I am very new to signal processing and coding which is why my questions might be really basic. I have a signal of the acoustic pressure p'(t) and I would like to use a third octave bandpass filter in ...
0
votes
0answers
71 views

Filtering frequencies in diferent ranges in Python

I would like to filter frequencies: Alpha, Beta and Gamma. These bands have a relation with the task that I want to classify, I am using the Gumpy python tool which has a method to apply Butterworth ...
0
votes
1answer
57 views

About the variance of the coefficient of narrowband noise when using signal-space representation

Assume that n(t) is a white Gaussian noise process with zero-mean and power spectrum density $N_0/2$. By using the signal-space representation, it can be expressed as: $$n(t) =\sum_{j=1}^N n_j \...
2
votes
2answers
190 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, ...
0
votes
1answer
31 views

Quadrature component - condition on equivalent lowpass signal

I have a question regarding the equivalent lowpass signal $x_{LP}$ of a bandpass signal $x(t)$ and the quadrature component. I'd like to find a condition on $x_{LP}(t)$ and $X_{LP}(f)$ such that the ...
3
votes
1answer
63 views

Is it possible to design a band-pass filter with fewer taps than a series HPF + LPF?

I am digitally filtering a signal that is streaming live. The goal is to reduce the filter delay as much as possible while maintaining the quality of some measurements based on the filtered signal. ...
0
votes
0answers
52 views

AWGN interpretation of bit error rate in time domain

I'll consider a 20 MHz bandwidth between 1.99-2.01 GHz. The carrier has been modulated by an OFDM signal (I/Q modulation) and is passed through a narrowband filter at the receiver. The noise that is ...
1
vote
1answer
63 views

Detecting phase difference between a clean and a noisy signal

I have a clean square-wave signal and a noisy signal from an accelerometer, perfectly synchronized to each-other but out of phase. I want to find the phase difference between them in real time, in ...
0
votes
1answer
62 views

LP to BP transformation steps

Considering the following problem, What i know to convert from LP signal to BP signal is to: Draw the FD of the LP equation From it I can draw the FD for BP From this graph I can deduce the equation ...
1
vote
1answer
140 views

Design of FIR and IIR filters in Matlab

I need to create 4 different pass-band filters. What remains the same throughout is the following: Sampling Frequency = $3000Hz$ Pass-band Frequency = $900Hz-1200Hz$ Now, these are the filters I ...
1
vote
1answer
125 views

Computation of parameter filter to match a given frequency response

I'm looking for the practical way to compute the parameters ($a_1$, $a_2$) of a digital filter to match a certain frequency response. I'm studying the 12-poles filter of the vintage component SP0256 ...
0
votes
1answer
1k views

Passband vs Baseband Bandwidth

Bandwidth is the difference between the upper and lower frequencies in a continuous band of frequencies. A key characteristic of bandwidth is that any band of a given width can carry the same ...
2
votes
1answer
110 views

Does a linear phase FIR filter shifted in frequency preserve linear phase?

Let's say I have a symmetric (and therefore linear phase) FIR low pass filter with real coefficients. If I then shift this filter in some direction in frequency by multiplying its coefficients with a ...
-1
votes
1answer
95 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=...
0
votes
1answer
363 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 (...
1
vote
1answer
63 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 ...
1
vote
1answer
510 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 ...
2
votes
1answer
194 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 ...
0
votes
1answer
58 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 ...
0
votes
1answer
99 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 ...
0
votes
2answers
291 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 ...
0
votes
2answers
845 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 ...
0
votes
1answer
74 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 ...
0
votes
0answers
76 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 -...
1
vote
1answer
566 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 ...
0
votes
1answer
100 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 ...
0
votes
0answers
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 ...
0
votes
2answers
86 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....