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Suppose we have 2 signals x(t) and y(t) with $$ x(t)=\delta(t)$$
If $x(t)$ is the input to a linear and time invariant system $S$, lets say we get a X(t) as the output:
$$ x(t) \overset{S}{\rightarrow} X(t) $$
If we have $y(t)$ as an input to the same system $S$, then we can predict the output of that system without k... |
Let's say that I have a system $H(z)$. What is causal inverse and how do I compute the causal inverse of $H(z)$?
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Let $x$ be 0, +1 or -1 with probability $1/2$, $1/4$, $1/4$, $\cdots$
What is the decision region?
I was asked this question during an interview. Can someone please give me a hint or source (from a conceptual point of view) to solve these types of problems?
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In the heavily cited paper by Harris 1978, there is a section on "Overlap Correlation" where he's using a "fractional overlap r" in his equation. Here is a screen shot from the open source paper linked above:
Can someone please help explain what's going on here? I'm trying to use equation 17 but I don't understand wha... |
I know wavelets were all the rage a few years ago, but I missed that boat and am wondering if it is worth putting significant effort into learning about them. My impression is that they were a little bit of a fad, and now have more limited applications than first assumed (similar to compressed sensing).*
My (very limit... |
I'm posting here because I don't understand why when we have a signal, let's say a voltage, the units of its sampled values are Volts multiplied by Hertz and not just only Volts? It's something I've seen in my course and this is what our teacher taught us but it's doesn't make sense to me.
He also taught us then the un... |
We’re developing a prototype using bladeRF and various Python scripts for processing IQ samples.
The system works mainly around 2.4 GHz frequencies: Wi-Fi and Bluetooth.
One of the needed functions is about CIR (Channel Impulse Response) estimation for the collected IQ samples on a specific frequency.
Question - are th... |
from the 5G NR manual shown bellow.
there is a diagram i have attache.
is there some intuitive explanation regarding why as the carrier spacing goes high then the slot time goes low.
how are these two connect together?
thanks.
https://www.sharetechnote.com/html/5G/5G_FrameStructure.html
|
TEXBAT is a recorded dataset about spoofing scenarios for evaluating GPS signal authentication techniques.
On this project, there are recorded GPS signals stored as complex 16- bit samples at a rate of 25 Msps.
I want to change its sample rate because maximum sample rate of my SDR (RTL-SDR) is 3.2Msps.
How can I change... |
Context:
I'm investigating using a DPLL to track input from a microphone. The mic will be capturing the output of a flute-like instrument. I'm trying to figure out how to configure the DPLL to track the mic input and I'm turning here for help.
Details:
I've implemented something like this:
... but I'm not having muc... |
This might not be quite the right forum, but with access to "consumer grade" memory storage and modern error correction algorithms, how long (order of magnitude) can data be preserved before it is rendered irrecoverable?
To further narrow the problem, assume you are starting with N perfect copies on separate but identi... |
I have computed the Q-Q plot of my dataset, which is a recording from a brain signal, and it shows a curious left and right skewness displacement, and I was wondering if this is any other distribution that I would infer from the graph. Since I am not expert in this area, I am a bit lost understanding the Q-Q plot. Woul... |
Assume we are trying to classify a sample $X$ as coming from one of two distributions:
$$
\mathcal{CN}(\mu, \sigma^2) \\
\mathcal{CN}(\nu, \sigma^2),
$$
where $\mathcal{CN}$ denotes a (circularly symmetric) complex Gaussian distribution with total noise variance $\sigma^2$, meaning it has $\sigma^2/2$ variance across t... |
High-resolution representations are essential for position-sensitive vision problems, such as human pose estimation, semantic segmentation, and object detection.
From HR-Nets we get semantically richer and spatially more precise resultant, what does this statement mean in the paper Deep High Resolution Representation L... |
Python deconvolution works fine when I convolve 2 signals in the full mode :
w = [1,2,3]
r = [4,5,6,7,8,9,10]
s = np.convolve(w, r,mode='full')
N= len(s)
from scipy.signal import deconvolve
recovered, _ = deconvolve(signal=s, divisor=w)
print('Convolved signal: ', r)
print('Recoverd signal: ',recovered)
Output :... |
I'm not able to convince a colleague on the following topic.
Statement: If, and only if, the sample frequency is sufficiently large and above the Nyquist frequency it does not matter what fs is as long as the signal length (in time domain) is constant.
Let's say we have a sinusoid with a frequency of 214 kHz. Let's say... |
I am currently studying for a test and I have this example:
Given the impulse response of a system:
$$ h(t) = \left \{ \begin{matrix}
1,& 0 \le t \le1\\
0, & \mbox{elsewhere}
\end{matrix} \right . $$
find the output signal of the system for the input signal:
$$x(t) = u(t)u(2-t)2t$$
Here is my progress so far:
B... |
Which wireless receiver has the better sensitivity for the same everything except the change in the Base-band de-modulation, one base-band demodulator for OQPSK and other base-band demodulator for MSK, which one gives better sensitivity ?
|
I am trying to follow along a paper: The IVO Software Blizzard 2007 Entry: Improving Ivona Speech Synthesis System
This paper explains how automatically estimated pitchmarks (certain time periods in human speech) can be corrected if they are obviously wrong.
They write:
3.2. Statistical Pitchmark Correction Method
We o... |
I have a more general question about $z$-transforms that I am having difficulty finding an answer to.
Suppose we have a two-sided sequence something along the lines of:
$$x(n)=a^{|n|}$$
where $a \in \mathbb{C}$ and $\mathbb{C}$ is the set of complex numbers.
How does the $z$-transform process change when part of the or... |
I'm trying to implement an Unscented Kalman Filter that tracks the amplitude, frequency, and phase of a multi-component oscillatory signal. Below is an attempt using the filterpy library in Python. I've tried to generalize the process of creating the KF, but can't get it to work for a single component with no noise.
... |
In massive multiple input multiple output (MIMO) case, I came across the following formula of throughput:
$\tau_{ij} = \bigl[\displaystyle\sum_{j\in \mathcal{U}}x_{ij}\bigr]^{-1}W_i\text{log}(1+\gamma_{ij}) \tag{1}$
where $j$ is the index of user, $\mathcal{U}$ is set of users, $i$ is index of Base station, $W_i$ is ba... |
Assuming there are 4 transmit antennas, do these four antennas share the bandwidth?
In other words, I wonder if these four antennas use one resource grid.
|
I'm trying to modulate array of bits with GMSK modulation with BT=0.3 . What I'm doing is making O-QPSK modulation for given bits, then applying Gaussian filter on I and Q arrays and after that converting it to MSK modulation. Gaussian filter seems to be applied correctly. However the resulting MSK signal does not look... |
I am having difficulty understanding the effect of quantization noise and ADC resolution in a digital PID controller.
I am also trying to understand the effects of sampling jitter on a PID controller.
Can anyone recommend any materials to help me understand these issues in closed loop, digital systems?
Thanks!
|
I get that for real time processing it's faster to IQ demodulate and filter, but if real time constraints aren't a factor, for raw precision and accuracy, what do we get out of lock-in amplification? Can we not simply take the FFT and just look at the information at the exact bin(s) corresponding to our excitation freq... |
I have observed that the Fourier transform of a tophat function is a Sinc-like function with higher peak sidelobes than an actual Sinc.
However, the Fourier transform of a Sinc is a tophat-like function with ripples in both pass-band and stop-band, and with slow transition.
My question is: why does obtaining a Sinc fro... |
The output of cross corelation shows the similarity between the two signals. But in what respect is there a similarity? I didn't quite understand how I should interpret the output. How should I interpret the output? I'm really trying to make sense of the underlying logic and output here rather than the math statement. ... |
I compute the NMF over a spectrogram (magnitude of STFT of a signal) in this way:
W,H = NMF(MyStft,r) # where r=2 is the rank
W and H respectively contain the spectrum and the temporal information.
My question is why? What's the logic behind that?
|
I have a custom-made image processing IP in a Vivado FPGA project which does not work properly. The VHDL logic is OK, I have simulated it outside the IP. The fault must be with the AXI interface and how I've connected it to the VHDL module. How can I debug the interface? With ILA? Where should I connect the probes? It'... |
I have been trying to estimate the power spectrum of a timeseries using fourier transform. I have tried to do this using two variations of the spectral density estimate using np.fft.rfft. The two functions are the following:
def TracePSD_1st(x, dt):
"""
Estimate Power spectral density:
Inputs:
u : time... |
I'm trying to match(to the best extent possible) the outputs of FIR filter based on Frequency domain overlap-save method and time domain convolution method resp.
I was able to get most of the output to match except the tail as shown in the figure below. The overlap-save method always seems to lose the last half cycle f... |
An information source produces a long sequence of three independent symbols A,B,C with probabilities 16/20, 3/20, and 1/20 respectively; 100 such symbols are produced per second. The information is to be transmitted via a noiseless binary channel which can transmit up to 100 binary digits per second. Design a suitable... |
I've noticed in some literature that the authors chose to use the mean and standard deviation of the extracted MFCC features.
"ANALYSIS AND VOICE RECOGNITION IN INDONESIAN LANGUAGE USING MFCC AND SVM METHOD",
Harvianto
Can you offer some insights as to why this approach is considered after the MFCC extraction?
I have... |
I know the structure of lattice and wiener filter. But I though FIR filter is always FIR (wiener, tap + delay) filter, But what is the advantage of lattice structure, which in the CMSIS DSP filter algorithms we have two FIR filter, one for wiener and another for lattice!
As you can see here in two name:
Finite Impulse ... |
I'm not an expert so I'm not sure if this has a name associated with this phenomenon or not, so I'm not sure what to search for; Perhaps this can be answered by pointing to some literature which I am unaware of.
I have a symbol which is 16 samples long, which is a sine wave. I generate input data of 256 samples long wi... |
The idea here is to improve a Sinc function by manipulating its Fourier transform.
As you can see, the tophat has ripples in the bands of interest and I want to eliminate them by smoothing them with a window or some filtering method, then take the DFT of the smoothed tophat to get the Sinc.
I want to compare the Sinc o... |
suppose I have a wavelet $\psi:\mathbb{R}\to\mathbb{R}$ satisfying $\int \psi(t)dt=0$. Do we also have that for all $j\in\mathbb{Z}$
$$
\langle f\,,\sum_{n\in\mathbb{Z}} \psi_{j,n}(t) \rangle = 0
$$
where $\psi_{j,n}(t)= 2^{-j/2}\psi\left(2^{-j}(t-n)\right)$ and $f:\mathbb{R}\to\mathbb{R}$ is some square integrable fun... |
For pseudo-random binary sequences, we know there are various properties: Autocorrelation, balance, Fibonacci vs Galois modes. These are all well-known.
However, for pseudo-random ternary sequences, I have been unable to find authoritative references. Where can I find a detailed exposition about PRTS sequences?
|
I have come across an undocumented slide detailing the system response based on a time vs amplitude input signal.
The transfer function $$G(jw)$$ and $$w_{n} = 2\pi f_{n} $$
$$h(t) = \sum_{k=0}^{n} A(w_{k}) \left[\cos(\psi (w_{k})) \cos(w_{k} t)- \sin(\psi (w_{k})) \sin(w_{k} t) \right]$$
Does anyone recognise this eq... |
I am seeking to understand, exactly, how to calculate a soft MLL output from a received BPSK signal, and what information is needed. I would like to implement turbo coding in my system, but the receiver is non-coherent, with a random phase offset and no channel state information available. I would like to know if it is... |
I recently came across this
$$ x(t) = \cos(6t) + \sin(8t) + e^{j2t} $$
signal that I want to find the fundamental period $T_{0}$ and fundamental frequency $\omega_{0} = 2\pi f_{0} = \frac{2\pi}{T_{0}}$ of but am having trouble doing so as I don't understand 1) how to determine if the fundamental period even exists and ... |
In this image from Understanding cascaded integrator-comb filters
The bottom image shows the output response, with the entire range as passband:
Even the CIC compensation filters are all passband to $f_s/2$.
Also on the same page:
As opposed to a 'normal' LPF, which has the passband end at some point < $f_s/2$:
How ... |
I want to resample a raster from 15m to 460m using a Gaussian filter.
The goal
I am having a coarse image which I want to downscale. I also have a fine resolution band to assist the downscaling. The downscaling method I am using is called geographically weighted area-to-point regression Kriging (GWATPRK). The method co... |
In the context of wireless receiver system design, what is the optimum choice of amplifier placement? Should the received signal be amplified first then filtered or should it be the other way round?
And what are the pros and cons in practical applications?
|
I've been reading and playing with the Hilbert transform in the context of extracting the envelope of functions, and I noticed something when playing around with a a simple case.
If we consider the solution for the undamped and resonantly driven oscillator,
$$x(t) = \frac{F_{0}}{2 m \omega_{0}} t \sin(\omega_{0} t) + A... |
Tools like waifu2x and Anime4k (for the MPV video player) can already easily de-noise and up-rez low quality images to 4k quality pretty darn well. Similar tools like DLSS and FSR are used for video games.
Are there any analogous tools for low-quality audio? That could properly de-noise it and make it higher quality? F... |
Does anyone have advice on efficient CIC Decimation filter implementation. I designed a basic 4th order CIC filter with a 64 decimation ratio in C (below).
I am currently testing this on a Sharc SC589 running at 450MHz, audio DMA's set at 48kHz output with 32 sample buffer giving me 300,000 cycles to play with in a cal... |
Wikipedia:
Huffman coding is optimal among all methods in any case where each input symbol is a known independent and identically distributed random variable having a probability that is dyadic. Prefix codes, and thus Huffman coding, in particular, tend to have inefficiency on small alphabets, where probabilities ofte... |
I am a bit confused regarding the implementation of Pulse shaping filter in OFDM (Both CP-OFDM & SC-FDMA) system. I am explaining my concept in the following,
The difference between CP-OFDM and SC-FDMA is the use of DFT block before subcarrier mapping.Reference.
I am not sure if I need implement pulse shaping filter ... |
I'm currently facing a filter that amplifies frequencies at the Nyquist frequency. The sampling frequency is $f_s = 10$ Mhz.
What's a typical application for such a filter?
This is how I generated the plots:
import numpy as np
import matplotlib.pyplot as plt
def fir(x, taps):
# Convolve signal with filter coeffic... |
Problem statement:
I am explaining my concept on The DAC implementation in 5G NR using an example.
For a CBW=20 MHz, SCS=15 KHz, the sampling frequency= 30.72 MHz. After the time domain signal generation, the time domain sample can be represented as,
x(t)=[0.5 0.2 0.3 .....] % [307200X1] taking 10 ms of sample
After... |
I'm a beginner in audio signal processing, and trying to calculate the amplitude of a .wav file. I've read some documents from the web and some other questions asked about this topic. However, I still don't know how to calculate the amplitude and sum of the amplitude contour (in dB) from a .wav file in Python. Hope som... |
I am attempting to use MIDI DDSP to synthesize midi file. However, I can't find how to convert these code lines to MIDI.
Here are the simple codes they've provided, and I didn't add anything, just followed what they've provided.
from midi_ddsp import synthesize_midi, load_pretrained_model
midi_file = 'ode_to_joy.mid'
... |
To measure True Peak, MathWorks's Matlab Help Center page suggests:
The signal is over-sampled to at least 192 kHz.
The over-sampled signal, a, passes through a low-pass filter with a half-poly-phase length of 12 and stop-band attenuation of 80 dB.
The filtered signal, b, is rectified and converted to the dBTP scale: ... |
I am trying to implement 3D-FFT on an IF signal to estimate range-velocity-angle. I was able to get the required results in range and doppler steps. However, when I am doing the angle FFT along the antennas, the range-angle map shows an object on the correct range but on the whole FOV, I tried this on 2 different datas... |
I want to detect jerk from accelerator data i.e. values beyond 1.57 m/s^2, but due to the high frequency nature of the sensor (400 values per second), it gives multiple jerks instead of one.
How can I solve this?
Result coming now
Desired result
I do not need more jerk updates as it gives many false positives. If ac... |
First, the definitions:
Definition (Gaussian process)
A random process $X(t)$ is a Gaussian process if for all time points, $t_1,\ldots,t_n$ the random variables $X(t_1 ),\ldots,X(t_n)$ have a multivariate normal distribution. In particular, the distribution of $X(t)$ at any time point $t$ is normal.
Alternate Definiti... |
Hardware
We have a homemade MRI machine (from the open source project openimaging). It has a single coil and B0 = 0.5 Tesla (enough for teaching).
Sampling Mask
We used a randomly generated sampling mask for a general single slice Spin Echo imaging:
In the sampling mask, each white line represents a phase encoding ste... |
I am reading the paper A Bias-Variance Approach for the Nonlocal Means.
One sentence from the paper is as follow:
To discuss the tuning of parameters of the NLM, we interpret this
choice as a bias-variance dilemma.
I encountered bias-variance for the first time in papers on image denoising and I'm not sure about the ... |
I'm very confused about downsampling in image processing and the use of sinc function to do it.
I read this post [1]: 2D Fourier downsampling some time ago that talked about my own doubt, that is to downsample an image in fourier domain (for personal knowledge). The answer of this post was to crop the center of the Fou... |
I'm an electrical engineering student studying statistics.
I saw in an article that White Noise variance = power = rms^2.
Could you explain how this expression is derived or recommend reference materials?
And in the case of discrete white noise, does the sampling frequency affect the variance a lot?
|
I have raw NIRS signal data measured during a study experiment and I would like to unify the signal lengths to avoid bias in analysis caused by longer signals.
Can I simply cut the samples out from longer signals to do this? Are there any considerations or other methods that should be taken into account?
Example: lengt... |
I am trying to simulate a radar-transmitted signal with a 4.5 Hz clock frequency and 1.8 GHz carrier frequency. I generated the carrier signal and a rectangle shape pulse signal, then multiplied in time. My pulse-width is 444ps. I have two questions about my results.
First of all, the result of the carrier signal seems... |
Let's say we have a system (for example an integrator) whose step response has a negative slope as shown by the MATLAB code below:
clc;clear ;close all
R=47*10^3
C=1*10^-7
num1=[-1]
den=[R*C 0]
sys1=tf(num1,den)
num2=[1]
sys2=tf(num2,den)
subplot 211
pzmap(sys1)
title('pole zero map for pure integrator, with -1 in nume... |
What is the relationship between signal processing and machine learning?
Is signal processing necessary or helpful before learning Machine learning?
|
I have a system described by the following difference equation:
$$y(n)−y(n+1) = 12x(n+2)$$
where $x(n)$ is the input, and $y(n)$ is the output.
How do I show that this system is time invariant and linear?
|
I was learning the decomposition of a signal into one even signal and one odd signal:
$$x(t) = x_{e}(t)+x_{o}(t)$$
with
$$x_{e}(t) = \frac{1}{2}\cdot [x(t)+x(-t)]$$ and
$$x_{o}(t) = \frac{1}{2}\cdot [x(t)-x(-t)]$$
But why do we do that? How does it help us?
|
My motivation to this post has arisen from the accepted answer to Amplitude modulation vs sampling rate?
Sampling the signal with the frequency close to $f_s/2$ can lead to some kind of "beatings" of the sampled signal. It is clearly seen if I try to sample simple cosine signal:
Here FFT shows both positive and negati... |
I have two signals
>> t = linspace(0, 10, 10000); % 0 to 10 seconds
>> u1 = 30*sin(2*pi*5*t); % Sine signal 1
>> u2 = 10*sin(2*pi*90*t); % Sine signal 2
>> u = u1 + u2; % Combine
>> spa(u, t); % Spectral analysis
>> grid on
And the spectral analysis shows these two signals u1 and u2
Now I want to filter the signal u ... |
I want to estimate the rolling average of a time series B using a Gaussian window. The equation to do this would correspond to
$$\tilde{B_{s}}(t_{n}) = \frac{1}{A_{s}} \sum_{t_{m}= t_{n}-3s}^{t_{n}+3s}B(t_{m})e^{-\frac{(t_{m} -t_{n})^{2}}{2s^{2}}}$$
where $$ A_{s} = \sum_{t_{m}= t_{n}-3s}^{t_{n}+3s}e^{-\frac{(t_{m} -t_... |
\begin{align}
L[e^{-at}u(t)] &= \frac{1}{s+a}\\
L[\cos(\omega_{o}t)u(t)] &= \frac{s}{s^{2}+\omega^{2}_{o}}\\
L[e^{-at}\cos(\omega_{o}t)u(t)] &= \frac{s+a}{(s+a)^{2}+\omega_{o}^2}
\end{align}
Everywhere $e^{-at}$ is multiplied with a function $x(t)$ and the new function becomes $$e^{-at}x(t) = y(t)\ \ {L \atop \leftrig... |
If I run this in matlab:
h = firpm(100,[0 0.1 0.2 1],[0 0 1 1])
and this in scipy:
h = remez(100,[0, 0.05, 0.1, 0.5],[0, 1])
I think I'm asking for the same thing, but the results are totally different and the scipy response is garbage. What am I doing wrong? I don't need the results to be exact, just similar.
|
Usually RSA encryption is used for internet security.
What are these disadvantages if we want to use RSA encryption to secure a radio communication?
|
I am using the following function to estimate the Gaussian window rolling average of my timeseries. Though it works great from small size averaging windows, it crushes (or gets extremely slow) for larger averaging windows.
def norm_factor_Gauss_window(s, dt):
numer = np.arange(-3*s, 3*s+dt, dt)
mul... |
I would like to synthesize a first order Gauss-Markov process from a white Gaussian noise.
I know from signal processing theory that it could be realized using a noise shaping filter designed properly (see Gauss-Markov process).
First order Gauss-Markov processes can be described from two key parameters: $\sigma$, whic... |
What do the following statements on pages 13 and 15 in this linked document mean?
DNL, a static specification, relates to SNR, a dynamic specification.
INL is a static specification and relates to THD (a dynamic specification).
I don't quite understand what kind of connection it is. What is the relationship between... |
If we give a input $x(t)=u(t)$ to a system $\mathcal{S}$ we get an output $y(t) = e^{-t} u(t)$.
After we Laplace-transform both the input and the output we get the transfer function
$$H(s) = 1-\frac{1}{s+1}$$ which in the time domain is:
$$h(t) = \delta(t)-e^{-t}u(t)$$
But why do we need to transform everything in the ... |
I'm trying to build a tool to automatically create a "background mask" of a scan of a postcard, allowing pixel information not relating to the postcard itself (ie. the ceiling of the scanner) to be transparent.
The attempts I've made so far have been wildly imprecise (often finding regions of transparency where it's lo... |
Suppose we have a system S and the relationship between $x(t)$ and $y(t)$ is $y(t) = x(t)+1$
However despite the fact the system is made of linear operators the system is not linear.How is this possible?
Can we have a system made of nonlinear operation but the system becomes linear?
|
I have a SIMO IIR filter represented as a state space system. I'm wondering if there is a canonical way of converting a IIR filter into a MIMO system, so I can calculate $N$ terms as input at once and output $N$ outputs with the least amount of FLOPs possible.
So far, I've found the following way to do it:
Assume our o... |
I know that MATLAB provides some built-in functions but I am not interested in those. I want to know how can we code to obtain the Rician fading channel gains from normal or Gaussian distributions. For example, the works in 1 and 2 define a Rician distributed random variable (channel amplitude) as:
\begin{align}
h\sim ... |
What is the actual relationship between Machine learning and Computer vision? Is Computer vision is subset of Machine learning or is it another independent subset of Machine Learning? I am trying to clear this confusion, some internet sources mention Computer vision is subset of Machine learning while some other mentio... |
The Fourier transform of an exponential function is a Lorentzian. For the sum of multiple exponential functions with time constants $k$, is it only meaningful to define the function and its Fourier transform on an interval given by the minimum and maximum time constant, since these values set the time scales for the sy... |
I am working with the following:
The script signalsim simulates one realization of a Gaussian stationary harmonic process according to
$$x(n) = A_1 \cos (2 \pi \frac{f_1}{f s} n + \phi_1) + A_2 \cos (2 \pi \frac{f_2}{f s} n + \phi_2), \quad n = 0 \ldots N - 1,$$
with frequencies $f_k = \{10, 20\} \ \mathrm{Hz}$, numbe... |
Is there any method via python of any other means, to return a list of wav files in a folder that are clipped?
I know that Adobe Audition can tell if a file is clipped, but I have to open up each file and then check. Can this process be automated somehow? Any direction is sincerely appreciated!
|
I would like to plot the power spectral density (PSD) of this signal
$$y(t) = x(t) + i(t)$$
where both $x(t)$ and $i(t)$ are binary phase shift keying (BPSK) signals with baseband bandwidths $W_x/2$ and $W_i/2$, respectively.
Assuming rectangular pulse shaping, each signal will have a $sinc$ PSD, which is centered arou... |
This is an open question, just for discussion. During my years studying and working on signal processing, I have identified several factors that are relevant for understanding any type of signal. For example, PSD for analyzing frequency spectrum and distribution of fundamental frequencies, if any; envelope of the signa... |
Given a known impulse response $h(t)$ and an observed signal $y(t)=(h*x)(t)+n(t)$, my aim is to recover an estimate of $x(t)$ in the presence of unknown additive noise $n(t)$.
If the mean power spectral density of $n(t)$ is known as a function of frequency, Wiener deconvolution is a simple and elegant solution to this ... |
I have EEG data recorded with a sampling rate of 256 Hz. Each recording contains 19 EEG channels. Other channels (like ECG data) are ignored. The recordings of 10 patients are 20 minutes long each, recordings of 2 other patients cover a period of 24 hours each. The long recordings contain sections where the recording d... |
We have a module in python that implements a digital filter. The type is not relevant. The filter coefficients have been designed to implement a particular response, but there is additional code and wrappers around the filter all baked into a class implementation. I need to validate that the filter module/class is p... |
So I need to implement a PI-controller and I found an Implementation of an PID-controller with some background explanation. I adapted the implementation to an PI-controller, implemented it and got the desired behavior.
I then proceed to read up on the topic in a text book (which is not publicly available, but I will pr... |
I have EEG signal data (19 channels) sampled at 128Hz. I am trying to retrieve the coefficients that are mentioned in a research paper included below.
To decompose an EEG signal, a digital FIR filter was used, which is based on a level-3 DAUB4 wavelet. The spectral Domain of the filter ranges between 5 and 45 Hz.
How ... |
I was asked which impulse response $h_1(t)$ or $h_2(t)$ has a better decoding performance for two filter lengths: $l_1 = 50$ and $l_2 = 500$.
$$h_1(n) = \cfrac{1}{\sqrt{l_1}}\cos{(0.2\pi n f/f_s)}$$
$$h_2(n) = \cfrac{1}{\sqrt{l_2}}\cos{(0.2\pi n f/f_s)}$$
with $0\leq n <l_k$ and $f \in$ [697 Hz , 1477 Hz]
The signal th... |
What is the frequency response of binning 2x2 pixels into 1 pixel in software?
Can the binning introduce aliasing?
Since the Fourier of the 2D boxcar function is a 2D sinc I would intuitively think that the sharp edges of the 2x2 filter would cause ringing in the frequency domain?
Would it not be better to window this ... |
I want to estimate the Power spectral density using Discrete wavelet transform and a Morlet Wavelet. Bellow you can find the function I am using. Any comments or suggestions on wether or not the following code is correct?
import pycwt as wavelet
mother_wave_dict = {
'gaussian': wavelet.DOG(),
'paul': wavelet.... |
In a typical sensor datasheet, there is a range of uncertainty for a given parameter. For example, there are min, typ and max values for the sensor sensitivity. In general, the datasheets do not provide information on how these values are obtained. Are these errors/uncertainties normally or uniformly distributed over t... |
Dft magnitudes conclusion from Richard Lyons [Understanding digital signal processing]
my verification code
pointno_iteration_times = 5;
for i = 0:1:pointno_iteration_times
log2_dft_point_num = 7+i;
dft_point_no = 2^log2_dft_point_num;
fsDataIn = 1e6;
freqInput = 5e4;
deltaT = 1/fsDataIn;
L... |
Yesterday I asked a question and got the answer to detrend my time series which I think is really better than applying a highpass filter. So I read the description of scipy.signal.detrend and there I learned that there is a parameter bp:
bp : array_like of ints, optional
A sequence of break points. If given, an indivi... |
A noisy signal with 500 MHz bandwidth, with negative SNR, when filtered to 6 MHz bandwidth, should attain a theoretical SNR gain of 20 dB. So if the original signal has -6 dB SNR, after filtering we should see the signal above the noise floor because SNR gain results in an attained SNR of +14 dB.
The signal was filtere... |
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