Newest Questions
29,007 questions
6
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1
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Window length clarification - FIR Filter
I'm reading an IEC standard and they say "Group delay of a finite Impulse Response (FIR) filter based algorithm with symmetric or antisymmetric
coefficients is equal to one-half of the window ...
- 3,879
0
votes
0
answers
24
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ber(eb/no)- how to get 1.75dB gap between rate=1/2 and rate=1/3? [closed]
I'm looking to do - BER(Eb/no)- for convoultional codes
how to find the gap =1.76db between rate=0.5 and rate=1/3?
i dont manage to do so.
i dont know how to copy the graphs, but these very old graphs ...
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1
vote
0
answers
24
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Accurate Function for calculating PSD-chatter index?
I was working on my research and I was adapting the Power Spectral Density Chatter Index from paper "In-Process Chatter Detection Using Signal Analysis in Frequency and Time-Frequency Domain"...
- 21
1
vote
0
answers
36
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Contraction of magnitude spectrum with increase in sampling frequency
I was implementing the cascade algorithm to obtain the D4 scaling and wavelet functions in MATLAB iteratively. The code can generate the functions properly, but the magnitude spectra I obtain depend ...
0
votes
1
answer
58
views
Correct unit for transfer function
I am trying to calculate the transfer function between one sensor with velocity timeseries data $y(t)$ and a witness sensor $x(t)$ which monitors position. Both sensors output data in volts, with a ...
0
votes
1
answer
15
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The flow of frames in a full synchronization chain in digital receivers
I have a full synchronization chain in a digital receiver that consists of:
Coarse frequency synchronization: this is a blind balanced quadricorrelator
Frame synchronization: this is data-aided ...
- 141
0
votes
1
answer
28
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Why does Python skimage.transform.resize give different results from MATLAB imresize for the same array?
I'm trying to replicate MATLAB's imresize behavior in Python using skimage.transform.resize. Here's my test case:
Python
...
0
votes
0
answers
16
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<GNURadio,SDR> Newbie to SDR. Plz help me
I am currently using the USRP b200 mini to copy what is shown on the site below.
https://kb.ettus.com/Transmitting_DVB-S2_with_GNU_Radio_and_an_USRP_B210
However, I found an issue where the usrp_sink ...
0
votes
0
answers
75
views
Computing inverse Fourier Transform for an even real signal
Given a real, continuous signal $x(t)$, which has a Fourier Transform $X(\omega)$ satisfying the property;
$$\ln\vert X(\omega)\vert = -\vert \omega \vert.$$
Find the signal $x(t)$, if we assume it to ...
- 187
0
votes
0
answers
10
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OFDM invalid packets, filtering problems in GNU Radio
I've been working on a custom OFDM implementation and I'm getting a lot of ...
0
votes
1
answer
25
views
OFDM timing algorithm in FPGA
What algorithm is typically used for OFDM (4G/5G) timing recovery in FPGA implementation?
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0
votes
1
answer
36
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Could anybody kindly help with this DVB-T problem?
In the DVB-T constellation chart, there are occasional, irregular, sporadic flickering points in the blank spaces between adjacent points.
The flickering points flicker within a fixed range, with an ...
0
votes
0
answers
43
views
Looking for some Time Dependant Fast Fourier Transform, FFT, tutorials
I am converting some image data to audio by altering the FFT frequency array, of a sound sample, using a 2D section, yellow square in video, as the manipulation data. At the moment its in discreet ...
0
votes
1
answer
43
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Two dimensional visualization of the Fourier shift theorem
I wanted to examine the simplest possible situation of the Fourier shift theorem. My interpretation of the theorem is this: Displacements in image space lead to phase changes in Fourier space. To that ...
- 159
0
votes
2
answers
64
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How to start building a piano note detection program (simple right-hand recordings, step-by-step approach)?
I’m currently working on my undergraduate thesis, which is related to digital signal processing.
The goal of my project is to create a program that can “listen” to piano recordings and convert what it ...
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0
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0
answers
17
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Question Isolating Speech From Clattering Noise - Similar Volume, Specific Issue
I have absolutely no experience with this field but have been trying to analyze some audio files where someone broke into my house (long explanation follows but can be skipped; more included because ...
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0
votes
1
answer
58
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16-QAM high noise? GNU Radio
I've been learning a bit about DSP recently and tried to build a working 16-QAM (or M-QAM) modem in GNU Radio, but haven't been successful.
I think the issue might be high noise caused by some of the ...
0
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0
answers
23
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Deadlock issues with simultaneous USRP RX / TX using UHD Python API
I'm trying to set up simultaneous RX and TX using the two front-ends on a USRP B210 using the UHD Python API. This resource recommends using separate threads for RX and TX, and this one says that UHD ...
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0
votes
0
answers
73
views
Orthogonality of Finite Samples of a Function and Its Delayed Version
Consider a band limited function $f(x)$ in $L_2(\mathbb{R})$ with frequency support in $[-B,B]$ . For small delays $\delta$ it is straightforward to show that $f(x)$ and $f(x+\delta)$ are not ...
7
votes
2
answers
156
views
Modified Remez halfband filter design
This question asked for the solution of the following problem:
Design an FIR equiripple halfband lowpass filter with unity gain at DC and with infinite attenuation at Nyquist.
The Remez algorithm ...
- 94.7k
0
votes
1
answer
34
views
When buffering a wrapper process at one length, and an internal process at another length, what is the logic behind the delay caused?
In an audio (or likely any data transfer context) processing scenario, at times it is necessary for an internal process which takes a fixed amount of data N to be wrapped by an external process which ...
0
votes
0
answers
21
views
Using very few hemispheres of data (1%) for particular pointing angles to determine impact on a huge number of hemispheres
Thank you for your time and I'll apologize for probably not explaining this problem well enough, but here goes. I have 20000 hemispheres of antenna patterns for 1x1 degree pointing directions and I ...
0
votes
3
answers
94
views
When a multi-tone signal with high dB input is applied, additional unwanted frequencies are observed in the frequency domain
In this setup, I’m using a MATLAB filter with flat coefficients applied across n channels. The left and right channels are then mixed to form a stereo output, which should ideally contain only the ...
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1
vote
1
answer
81
views
Rfft giving freakishly small amplitudes
I have a very annoying Problem (I am very much a noob when it comes to dsp so please bear with me):
I have a periodic signal with an amplitude roughly one. However, at periodic intervals, the signal ...
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0
votes
0
answers
34
views
Data Preprocessing for FTIR
I need to analyse some spectra obtained using FT-IR (Fourier Transform Infrared) Spectroscopy. I am mainly interested in increase/decrease of a specific molecule after some sort of procedures. I am ...
0
votes
5
answers
151
views
Why isn't a Dirac pulse considered white noise?
It is probably a basic question, but why isn't a Dirac pulse considered white noise ?
To be fair, I intuitively wouldn't consider it as such, but the defining characteristic of white noise is that the ...
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0
votes
0
answers
24
views
Cross-Synthesis Algorithm Help
If I'm trying to create a cross-synthesis/spectral morphing effect between two signals in real-time using an stft (similar to a plugin like Melda's MMorph or Zynaptic's Morph 3), what would be the ...
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1
vote
1
answer
71
views
Interpolation error between even and odd FFT
Upsampling a spike [100 0 0 ...] with rfft - irfft
gives quite different results for input lengths even or odd.
Here's a plot for 100 and 101:
Why the difference ? ...
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0
votes
1
answer
43
views
How to convert measured insertion loss to an impulse response through ifft? Question around factor of 2
Specifically I'm unsure about a factor of 2 scale factor when converting the measured insertion loss to a double sided spectrum, necessary for the ifft.
In the past I have always believed that ...
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0
votes
0
answers
49
views
Spread Spectrum spreading code
How can a spreading code be designed to produce a flat energy spectrum, ensuring uniform energy distribution across all frequencies?
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-2
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0
answers
35
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Is it possible to find the error location polynomial in t cycles for Reed–Solomon Code using a modified RiBM algorithm?
Recently I've read a paper on Reed–Solomon Code, in the decoding part, the author proposed a modified RiBM algorithm which use t cycles(while RiBM algorithm needs 2t cycles) to find the error location ...
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3
votes
1
answer
135
views
scipy remez half-band filter DC gain
I'm trying to use scipy.signal.remez to design half-band filters. My understanding is that this targets an equi-ripple criteria to design the filter. What I am ...
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0
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0
answers
39
views
0
votes
0
answers
23
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How do I generate proper QAM-M modulated passband and save it as WAV file?
I'm new to digital signal processing and would like to know how to make a QAM-M modem that generates proper passband signal and saves it as a WAV file.
The tool should allow me to specify the carrier ...
4
votes
3
answers
697
views
What is the best way to assess audio quality in an embedded or Android system?
In recent posts, Evaluating THD for any Test Tone and any Sample Rate, I have attempted to assess the audio quality of my Android device by using Oboe in Native C++, and evaluate THD in real time ...
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0
votes
0
answers
47
views
Matched filtering or other DSP for air-sonar or echo timing of audio ping
Working on an air-sonar device and looking for a practical development sequence and DSP filtering strategy that can reliably identify and time the RX of a known TX short audio ping. Some research ...
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0
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0
answers
78
views
Evaluating THD for any Test Tone and any Sample Rate
I'm writing as a follow up to this:
Evaluating THD+N in C++ on the Fly
I am using C++ where FFT computation is restricted to time windows which are powers of 2. I am using KissFFT, because it was the ...
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0
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1
answer
47
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Checking periodicity for a continuous time periodic signal
I am working on finding Fourier Transform for a signal given by
$$ x(t) = \sum\limits_{n=-\infty}^{\infty} e^{\vert t-2n \vert} $$
I got a hint that this sign is periodic with period, $T = 2$.
But to ...
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5
votes
1
answer
60
views
Kalman Filter with Out of Order Measurements/Negative Time Step
I'm designing a Kalman filter for a navigation system. Unfortunately, some of my measurements are going to come in out of order. I know the best solution is to buffer the measurements and process them ...
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0
votes
0
answers
34
views
bandwidth of square root raised cosine filter
I am trying to understand the output bandwidth of a Square Root Raised Cosine filter.
I have these parameters in the system:
The DAC sampling rate is 5GHz.
The symbol rate is 2.5GHz so I have 2 ...
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0
votes
1
answer
50
views
Is any information lost when computing an IFFT on a single sided spectrum vs the double sided spectrum?
I've known for a while that it is important to use a double sided spectrum when performing an IFFT in order to ensure the recovered time domain signal is purely real. However I've also seen that using ...
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0
votes
0
answers
56
views
Third order PLL stability
In a one of the publications I encountered following statement:
"The 3rd order PLL, while being more flexible in front of high
dynamics, only remains stable for bandwidths below 18 Hz."
...
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0
votes
0
answers
26
views
Averaging coherence across segments/epochs/animals: pool spectra or average coherences?
I’m getting advice from an LLM on this, but I’d like humans to weigh in. I have LFP data from two brain regions. It’s segmented many ways, listed from lowest to highest level:
by uninterrupted ...
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0
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0
answers
34
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OFDM Radar 2D Periodogram – Normalization inconsistency between signal and noise estimation
I’m implementing a 2D-OFDM radar (SISO) simulation based on the paper “Maximum Likelihood Speed and Distance Estimation for OFDM Radar” by Braun, Sturm and Jondral.
The system transmits MPSK-modulated ...
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0
votes
1
answer
101
views
Evaluating THD+N in C++ on the Fly
I need to compute THD on the audio coming in from my microphone. I have successfully written the required C++ to capture the audio and process it. Now I need to compute THD properly. I used chatGPT ...
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0
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0
answers
30
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Signal limited in time but not in bandwidth [duplicate]
The signals we transmit are limited in bandwidth and time. But is it possible to transmit a signal that is limited in time but not in bandwidth? For example, emitting white Gaussian noise of duration ...
3
votes
0
answers
60
views
Rounding errors in best linear approximation of a system
I am working on the orthogonal decomposition of a signal to compute the best linear approximation of a system. Given an input signal $x[n]$ and system output $y[n]$, the output can be decomposed into ...
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0
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1
answer
36
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OFDM up-/downconversion: relation between $f_s$ and $f_c$
I have really hard time trying to wrap my head around how sampling frequency of baseband OFDM signal relates to carrier frequency and how baseband signal is upconverted / downconverted.
Baseband ...
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1
vote
1
answer
81
views
Implementing an analytic signal generator in MATLAB
I am trying to implement the analytic signal generator proposed by Clay Turner: [here]http://www.claysturner.com/dsp/ASG.pdf:
I have coded the MATLAB code as follows:
...
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0
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0
answers
31
views
Minimum $C/N$ and $E_{b}/N_{0}$ for 64QAM at a Given Bit Error Rate
A 64QAM transmitter operators at a bit rate of $120\space\text{Mbps}$,
for a probability of bit error of $10^{-5}$. Determine the minimum
$C/N$ and $E_{b}/N_{0}$ for a receiver bandwidth equal to the ...
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