Questions tagged [algorithms]

Algorithm is a method expressed in a finite list of steps of well-defined instructions to process a signal.

Filter by
Sorted by
Tagged with
0
votes
1answer
23 views

What is the input dimension for LMS update algorithm

I just realized this forum existed, posted my question on the wrong forum. Sorry about the formatting, please don't hesitate to ask if any part of this post is unclear. This is my first post. I'm ...
1
vote
1answer
36 views

How do you map indices to twiddle factors in FFT

I am kinda lost on how to map my indices for each stage to my look up array of precomputed twiddle factors. For an $N=8$ point FFT i have $N/2$ twiddle factors in total: ${ [0] = W_8^0, [1] = W_8^1, [...
0
votes
0answers
16 views

image processing, edge enhancement

*Hello I used k mean method to detect edges and that’s my results as shown in the pic but I want to get more accurate results so I need to enhance my edge detection more what methods would you suggest ...
1
vote
1answer
29 views

Effectively extracting “real” data from a noisy dataset

This question was originally posed to Math SE. It was suggested that DSP SE would be more suitable. Background & Motivation: I have three lists of timestamps (UNIX timestamps, plus a subsecond ...
2
votes
1answer
41 views

FFT seems more accurate than MUSIC algorithm?

I created a signal with two sinusoids and added increasing amounts of random noise to it. The results of running the FFT and MUSIC on this signal are shown in the image below. Ignoring the fact that ...
0
votes
0answers
38 views

How can I implement a phase detection algorithm with my amplitude detection?

I have been recently working on a signal detection problem in Matlab. At the minute I am detecting signals based on their amplitude, using an m-of-n detector. I am interested in improving the false ...
1
vote
0answers
27 views

If a function has slowly varying amplitude and phase what is the bandwidth of the amplitude and phase individually?

I am dealing with time histories that are narrow band with slowly varying amplitude and phase. I wish to extract the amplitude and phase but there is noise on the time history. An example of the type ...
0
votes
1answer
19 views

Why use both packet detection and symbol timing offset in WLAN 802.11?

In IEEE 802.11 Wlan, at the receiver side, we first use packets detection algorithm to detect the start of the packets, and then uses fine symbol timing estimation algorithm to find the start of the ...
3
votes
2answers
3k views

Why do we need DFT when we already have DTFT?

We already have DTFT so why do we need DFT? Please don't write DTFT is used for discrete, aperiodic signal which transfers in the frequency domain to periodic and continuous, but in DFT is discrete ...
0
votes
0answers
26 views

Communicate to user that SNR is too low - Speech procesing

I am working in a project to estimate the signal to noise ratio (SNR) for an automatic speech recognition system in order to generate an alert to the user if the noise is too high in the place where ...
0
votes
0answers
33 views

DFT algorithm designed for a “sample-by-sample” senario

Suppose I have a system that wants to take an input signal (audio in this case) and wants to output a Discrete Fourier Transform of it in real time (ie every sample). My initial thought is that if you ...
0
votes
0answers
30 views

Goertzel filter for non-equidistant sampling

We have a sensor that reports a new value asynchronously only when the value changes. Therefore, we receive samples at arbitrary time stamps. We basically receive value + timestamp of the measurement ...
0
votes
1answer
66 views

Wrong values calculating FFT with EEG Bands using Numpy

First of all I have to say I am very new to these matters. I am trying to apply FFT algorithm to some values obtained by EEG bands. I found the following code but I am unable to make it work correctly....
1
vote
1answer
53 views

Minimize the Cost Function of Values of Vectors Based on Their Amplitude

I have two vectors $X = [x_1,x_2,x_3,x_4]$; and $Y = [y_1,y_2,y_3,y_4]$; I know that $|x_1|$ = $|y_1|$, and $|x_2|$ = $|y_2|$,... so on. it means the difference is only in the sign. it might be ...
1
vote
1answer
120 views

MUltiple SIgnal Classification (MUSIC) Implementation

I have a linear 4 element antenna array currently in my design, I am able to obtain the I/Q data from each antenna. Now I am trying to implement the MUSIC algorithm to obtain the AoA (Angle of Arrival)...
1
vote
1answer
80 views

FFT algorithm gives wrong signs on my output numbers

I was told from another stack exchange (stackoverflow and computer science stack exchange) to post here - so hopefully now i can get some help from people who understand the algorithm, but if this is ...
1
vote
0answers
23 views

Is my implementation of Generlized Pencil-of-Function correct?

I have a time-series data that should be of the form $$ f(t) = \sum_nA_n(e^{\alpha_n t}+e^{-\alpha_n(T-t)});\;\alpha_n=\eta_n+i\omega_n;\;i=\sqrt{-1} $$ and I want to find parameters $A_n$, $\eta_n$, ...
1
vote
0answers
32 views

Asymmetry In The Mirroring Of An FFT Of A Sinusoidal Signal

I am trying to implement a Cooley-Tukey FFT algorithm in its iterative version. Specifically, I am implementing this Wikipedia pseudocode (please look at the section Data reordering, bit reversal, and ...
2
votes
1answer
59 views

Clear examples of Fixed Point Algorithm Specification Block Diagram for FPGA Implementer

I have been working on converting a simple, floating point algorithm to fixed point and need to create a block diagram to help the guy who will implement this on an FPGA. As often is the case, the ...
1
vote
1answer
155 views

Algorithm that Fills the White Holes Within the Character Image

I have this degraded image : Using paintbucket tool in Paint.NET Windows application, I fill the character image black. My ...
0
votes
0answers
21 views

Remove background, keep black characters

I use ID scanner machine (link) to remove the background. The result is the gray image below. It seems that the scanner uses IR to do that. Is there any algorithms to obtain the same result? Thanks in ...
1
vote
1answer
79 views

Discrete Wavelet Transform output: coefficients or FIR-filtered signals?

I have a theoretical question about the calculation of the Discrete Wavelet Transform, using MATLAB specifically. According to this video-tutorial on the MATLAB lagorithm: https://it.mathworks.com/...
0
votes
1answer
21 views

Implementing an L-System conversion from R2 to R1 for symmetric, square matrices

I have been reading for some time about L-Systems, and specifically the Hilbert Space filling curve. I am interested in writing a function to convert upper-triangular matrix coordinates into an ...
0
votes
1answer
67 views

Upsampling implementation

I have problem with upsampling implementation in the following way: My code: ...
0
votes
0answers
461 views

Mapping ring asteroids in Elite Dangerous by image processing

In the game Elite Dangerous, which is an online spaceflight-based sandbox game set in a procedurally-generated galaxy, one of the most profitable in-game occupations is mining commodities from ...
3
votes
1answer
109 views

Algorithm to Count Zeros Outside Unit Circle for FIR Filter

As detailed in this post Can I set a constraint on the first tap of an FIR filter such that its inverse is stable? I show how Cauchy's Argument Principle can be used to easily confirm if an FIR filter ...
1
vote
1answer
76 views

What is the difference between time complexity and sample complexity?

What is the the difference between time complexity and sample complexity in the context of algorithm development? I'm currently studying the sparse Fourier transform and this idea of sample ...
0
votes
0answers
32 views

What is the technical term to join two signals with different phases?

there is a name for this: If I have two signals with a discontinuity, arrange the phases of one signal to fit the other and not see the discontinuity.
1
vote
0answers
65 views

Why does the griffin lim algorithm work?

the griffin lim algorithm works to reconstruct audio from a magnitude spectrogram, but i don't understand how reusing the same spectrogram every iteration with noise can produce decent sound How from ...
0
votes
0answers
13 views

Question regarding the implementation of the guided random walks algorithm

I'm working on the implementation of the paper: Segmentation by retrieval with guided random walks: Application to left ventricle segmentation in MRI. I tried to modify the weights functions mentioned ...
1
vote
0answers
97 views

Is there a FFT algorithm which is both in-place and constant geometry?

I work in crypto where the NTT (Number Theoretical Transform) which is just a FFT in finite fields is used. I wanted to know if there exists an implementation of the FFT which is both in-place and ...
0
votes
1answer
61 views

RF signal identification algorithms

There exist many, many analog and digital data transmission protocols. It is often difficult to tell which mode one listens to and tedious to do for many signals. In Ham Radio, a Reed-Solomon ...
1
vote
1answer
48 views

How to compute an old style shore line drawing?

I wish to represent a shore line, old-style, as in the following image (city on the left, water on the right): UPDATE: new image for another example of what I'm after, namely the thin lines (given ...
1
vote
1answer
98 views

How CDMA receiver extract it's corresponding data from the receiving modulated & superposition-ed signal?

I have difficulty understanding CDMA. I have read all those PN/walsh code things, and understand orthogonality very well. But none of the resources I found demonstrate how a receiver end extract ...
8
votes
3answers
295 views

Best Approach to Rank Complex Magnitude Comparision Problem

This is in reference to the responses for an efficient algorithm for the comparison of bounded fixed point complex numbers at this post. Efficient Magnitude Comparison for Complex Numbers See the ...
0
votes
1answer
208 views

The selection of the amplitude of the signal, consisting of rectangular pulses, at different frequencies

I already asked a similar question, but did not receive an answer and did not find a solution, I want to make another attempt to get to the bottom of the truth. There is a signal consisting of ...
18
votes
9answers
2k views

Efficient Magnitude Comparison for Complex Numbers

Is there a more efficient algorithm (or what is the most efficient known algorithm) to select the larger of two complex numbers given as $I + jQ$ without having to compute the squared magnitude as $$...
1
vote
1answer
153 views

Separation of signals without loss of information about the signals themselves

There is a signal that contains: Rectangular pulses on frequency of 1 kHz Rectangular pulses on frequency of 1.4 kHz Other noises. Required: Separate 1kHz pulses from everything else and measure ...
0
votes
0answers
21 views

Finding Duplicate Pixel/Objects along Image seams

I have a seam of two photos joined by a seam alignment algorithm that on occasion generates duplicated pixels/objects/artifacts on both sides of the seam in the final, aligned photo. The images are ...
0
votes
2answers
548 views

Understanding Voss-McCartney pink noise generation algorithm

I'm implementing the Voss-McCartney pink noise generation algorithm. If you follow the link above, you can read: from James McCartney 2 Sep 1999 21:00:30 -0600: The top end of the ...
0
votes
2answers
202 views

how a signal for which calculate RMS can be filtered and have a fast settling time?

i designed a sinusoidal pwm amplifier (3KHz to 20KHz) that regulates its output voltage reading the RMS value of output current. The RMS is obtained squaring the signal sampled by AD converter @...
2
votes
1answer
113 views

One Too Many Non-Zero Eigenvalues in MUSIC DF Algorithm

I'm working on simulating the MUSIC algorithm in MATLAB to determine the azimuth angle of arrival of a simulated signal. My virtual antenna array consists of 4 antennas arranged in a plane. While I ...
1
vote
0answers
75 views

Space-Time coding uses large amount of block codes to acheive maximum spectral efficiency

Assume I have a MIMO system with $M=8$ transmit antennas, and an arbitrary number of receive antennas. This MIMO systems uses space-time coding. the block codes (matrices) transmitted are part of a ...
1
vote
1answer
137 views

Understanding Fourier Transforms in abstract math terms

I am having a hard time implementing a method that computes Fourier transform coefficients for the complex form using the trapezoid rule. I have floated questions in the math and stackoverflow ...
1
vote
1answer
87 views

Fuse two sources of linear acceleration with a Kalman filter

How would I fuse two different sources of linear acceleration with a Kalman filter (perhaps linear acceleration readings from an IMU and from a dedicated accelerometer)? My state is defined by ...
0
votes
0answers
54 views

Range Migration Algorithm in FMCW MIMO RADAR

I’m using a FMCW MIMO radar [77-79 GHz] with a virtual linear array made of 48 channels. I’m wondering if the adaptation of the range migration algorithm (typically used in SAR processing) is ...
0
votes
0answers
67 views

State of the art for automatic rhythm analysis

What are the currently most used and less error prone algorithms in the field of music information retrieval for beat detection and tracking?
4
votes
2answers
100 views

Idea for Noise Level Estimation / Automatic Thresholding in the Presence of Peaks

I have the fft of some signal, and want a rough estimate of the noise level in order to choose an appropriate threshold for our peak detection algorithm. In general, the fft contains mostly noise with ...
1
vote
1answer
343 views

Understanding a lowpass - comb filter implementation

I try to understand the implementation of the low-pass comb filter of the Freeverb reverberation algorithm: https://ccrma.stanford.edu/~jos/pasp/Lowpass_Feedback_Comb_Filter.html The original ...
0
votes
1answer
314 views

Need Help with Time-Stretching WSOLA Algorithm

I’m having problems implementing time-stretching using the Wave Similarity Overlap Add (WSOLA) algorithm. I got the basic OLA algorithm working first and then added wave alignment using cross-...

1
2 3 4 5
8