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1
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3answers
61 views

Algorithm for detecting the time where the signal is above a threshold

I need to detect the time window where a 1D-signal is above a certain threshold. If it dips below the threshold briefly I'd like to merge the two windows, if it dips below for a longer time, split ...
3
votes
3answers
70 views

What are the differences between notch filter & Goertzel?

I would like to integrate in my application a tone detector but I'm confused between 2 kinds of filters: Goertzel or Notch? I saw that Goertzel is a recommended for tone detection. But - what if I ...
0
votes
0answers
14 views

Zero Cross Rating synchronization

I send some pure sinuses that are representing bits. I found that after some bits the system is losing synchromization so for example: if I want to catch a 13Khz sinus I get 12.8K. I use ZCR to ...
0
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0answers
27 views

Binary FSK optimal detection rule

Let us consider BFSK modulation with symbols $\in {{1,2}}$. For symbol m the transmitter sends $s_m(t)=\sqrt{P\over T} e^{j2\pi f_mt}$ where $m=1,2$ and $f_m$ is symbol's $m$ carrier frequency. The ...
0
votes
0answers
19 views

BFSK software demodulation with zero crossing rate - sync problems

I try to decode my bits which are seperated by 100 Hz: '0'=13KHz, '1'=13.1KHz. Now, I'm just trying to send 8 bits in a 15msec ...
0
votes
1answer
73 views

What are the alternatives to FFT for computing high-resolution tone power levels?

I have a system where there's a transceiver which transmits tones on specific frequencies (about 260kHz) and a receiver which is supposed to recognize those tones. The transmitted tones are of low ...
0
votes
1answer
55 views

Detecting FSK near real time with c#

I try to detect some FSK signals made by audio in near real time. I know that I will get some latency. In the start I try to detect some tones of 10Khz in a duration of 75ms. That is achieved by a ...
0
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0answers
39 views

Signal reconstruction in FMCW radar

I am doing fmcw radar simulation. I have an output of mixer and from that I want to reconstruct the amplitude and phase of the signal. Therefore, I am taking hilbert transform and by the ...
0
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0answers
19 views

Identify correlated colored noises that affect a signal

In the process of signal + noise, which is not stationary. In this case how could I a. determine what autocorrelated noise colors affect a signal. b. What mix of correlated colors affect the signal ...
0
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0answers
17 views

Criteria to distinguish good/bad response to Intermodulation

I am actually studying the effect of intermodulation on multiple devices which are basically building element that contain amplifiers FPGAs and ADCs. I know for a fact which unit is bad and which is ...
0
votes
1answer
34 views

What is the right algorithm to detect segmentations of a line chart?

To be concrete, given 2D numerical data as is shown as line plots below. There are peaks on a background average movement (with small vibrations). We want to find the values of pairs (x1, x2) if those ...
2
votes
2answers
42 views

Any basic paper on biomedical signal processing to practise with?

I am quite interested in biomedical signal processing and I am looking for some biomedical signal processing papers in order to reproduce the results that they obtained. The idea is to redo what they ...
3
votes
2answers
68 views

This is about signal processing in the first radar

I read in a book that the first radar was a CW one that was used to detect ships. Since it was CW, did it use Doppler to detect the moving ships? What was the signal processing used in it? Is there ...
0
votes
1answer
163 views

Synchronizing data sent over sound beeps with Goertzel Detection, C#

I'm trying to send some text over sound. For example, I try to send the words "Hello John". I do it this way: Every char is converted into its binary ascii code. Then I construct a wav file with no ...
0
votes
1answer
39 views

Ways to identify if music has vocal timbres in it?

The human voice is singular because it has a specific frequency spectrum and fast transitions between vowels and consonants. What are good and computationally fast ways to detect if there is probably ...
0
votes
1answer
41 views

Far field spherical waves plane waves

All em radiation propagates spherically and at a far off place a small enough distance, when observed appears like a plane like our experience on the earth. So I tend to think that whether a wave on ...
2
votes
1answer
92 views

Detect dog barks

I’d like to use my Raspberry Pi to record when and how often my dog barks. But for privacy reasons, I don’t simply want to record the loudness in the room, so I have to automatically detect barks. ...
0
votes
2answers
96 views

adding noise to a signal

I have an audio file. I took an extract of the file called variable "CALL", and I took another extract from the file which is just filled with background noise, called "BACKGROUND". Using matlab, I ...
0
votes
1answer
63 views

Matlab: if given nothing but an audio file, how do I modify it to produce incrementally lower signal to noise ratios?

I have an audio file with a high sampling rate of 250khz. It contains animal noises. I've built a program which counts all the animal noises. However, I want to find out how robust the program is and ...
3
votes
2answers
82 views

Create Matched Filter Reference Signal when Scaling Unknown

I am working on a problem which raised what should be a simple question, but I'm stuck on it. The objective is to detect a shifted and scaled version of a known signal in the presence of Additive ...
0
votes
0answers
7 views

use of recurrence quantification analysis for deterministic signal identification and classification

The recurrence quantification analysis (RQA) is a method of nonlinear data analysis which quantifies the number and duration of recurrences of a dynamical system presented by its state space ...
2
votes
0answers
30 views

Signal conjugation detected on RF recording samples, why?

I collected spread spectrum signals at 400 MHz at low elevation angles using Software Defined Radio complex sampling over the seasons. I noticed that over watery, icy surfaces, the RF samples are ...
0
votes
0answers
24 views

Finding periodicity within sequence of time hacks

I have a series of time hacks for various events that have occurred. Some of these events occur at regular intervals (+/- some small variance) but I do not know what those intervals are and would ...
3
votes
1answer
272 views

What is the theoretical upperbound of information that could be transmitted by a device per second?

Suppose I would like to stream data from a device in a single second. What would be the theoretical upperbound of the amount of information (in bits, bytes, pixels...) that could be sent during this ...
0
votes
0answers
38 views

AR-like marker detection

Let's say I have a grayscale image in which I wish to detect (and later identify) a marker. It is also my task to construct an appropriate marker. As image is grayscale that means the marker should ...
0
votes
0answers
16 views

Calculating Dynamic Time Warping

I am trying to implement a DTW algorithm but I keep getting infinity as the result. I implemented three functions - DTW which is the actual algorithm, ...
-1
votes
1answer
93 views

Feature extraction for sound recognition and classification

I am building an application that would "listen" to the microphone input, analyse it, and compare the analysis to a pre-analysed and pre-classified sound bank (small - maximum 20 sounds). It will then ...
0
votes
0answers
91 views

Time frequency domain analyis of signals

In the time frequency domain I have used the following denoising methods Thresholding or schwirnking - Soft,Hard,Median and with methods (minimax, adaptative and sure). However if recomposing the ...
1
vote
3answers
124 views

Need critical help: How to detect and distinguish two very similar looking signals?

Hi guys I have a really tough signal processing question here. How do you detect and distinguish two very very similar looking waves? I need to distinguish between these two signals for an online ...
1
vote
3answers
99 views

Good way to detect pulse with known width with background noise?

I'm dealing with a light sensor tracking a bursting LED. Unfortunately signal is weak and there are other light sources in environment. I've used optical filters on sensor but there is still some ...
2
votes
3answers
187 views

How to determine SNR from FFT of measured data?

I am doing impedance measurements, where I do a frequency sweep of a test current, and I measure the resulting voltage. Offline, I compute the FFTs of the voltage and current, and I want to make sure ...
0
votes
2answers
65 views

How does 3D Time-of-Flight (TOF) camera work?

This is my first post in this forum! So Point me if anything is not clear! I want to know how TOF camera works? So I've done Google & read some nice explanation about How Phase difference between ...
0
votes
1answer
152 views

What is the Intuitive description of circular symmetric complex zero mean white Gaussian noise?

Suppose we have an added discrete noise signal defined as: $$y[n]=x[n]+w[n], $$ where $w$ is zero mean white Gaussian noise. Question: When we say white noise, is it sufficient to say that it is ...
1
vote
1answer
95 views

Unsupervised learning algorithms to detect anomaly in waves

I have a sample of graphs (more than 10000...). that look like in the image below: I am searching for an unsupervised learning algorithms that can help me to detect anomalous observations. Here ...
0
votes
1answer
58 views

One representative time series signal from multiple time series data

I came across this basic problem in DSP which is not my area owf expertise but I consider this problem to be a common problem which others might be addressing. I have multiple time series data and I ...
0
votes
0answers
170 views

Problem in Implementing Cyclostationary Feature Detector in Matlab

I have Implemented this detector in AWGN channel in Matlab but I am getting vague result. As it performance doesn't vary with change in SNR. Its very strange result for me. I don't know what mistake I ...
0
votes
2answers
89 views

“Perfect waveform” for cross-correlations?

I am well versed in cross-correlations, as my masters thesis heavily relied on them for music classification and beat detection. So this question focuses more on the signals that I am running an ...
0
votes
1answer
93 views

Is it possible that adding noise to a signal can increase detection possibility?

I am simulating a feature detector in noisy environment which consist of AWGN Noise and Impulsive Noise. But I am getting a strange result as Signal with Impulsive+AWGN noise has better detection ...
1
vote
2answers
559 views

Simple and efficient algorithm to detect frequency and phase of a sine signal

I need an algorithm to detect frequency and phase of a pure sine signal. The frequency of the input signal changes between 0 and 100 Hz. The value of the signal gets captured with a frequency of 20 ...
0
votes
0answers
47 views

Adaptive filtering for detection of a known-frequency periodic signal

Given a very noisy signal (EEG recording), to identify which periodic component is stronger, out of $N$ (e.g. $4$) known frequencies. For the sake of completion, the application is an SSVEP-based ...
1
vote
1answer
97 views

Detecting a frequency swept sinusoid and its parameters?

Given a (FFT-sized) frame of data, and detection of a spectral component statistically above the noise floor in the FFT of this window, what characteristics or signal analysis could be used to ...
1
vote
1answer
214 views

Why these harmonics always present?

I am using Audio Precision 2700 to test some test vectors. I have connected resistor banks as class - d power amp's load, and tap from this resistor using a XLR cable to the AP. When my power amp ...
0
votes
1answer
50 views

how to detect signal noise

I have data from a power transformer that has a frequency of 60 hz. Sometimes there are faults in the system and causes a large spike in the reading of the transformer. What I want to do is run the ...
0
votes
0answers
57 views

Simplest approach to classify signal based on its 'smoothness'?

First of all, I have no experience with signal processing whatsoever and I may not even use proper terms so please bare with me. I am just humble software developer trying to find the simplest and the ...
2
votes
2answers
317 views

Thoretically, what makes multi-pitch detection so difficult?

For multi-pitch detection, I mean for example pressing several piano keys at the same time. For signal pitch detection (pressing one key at a time), after FFT, mostly the frequency with the largest ...
1
vote
0answers
27 views

Variation in Signal Power in Mimo system

I am exploring methods for reducing computations required by MUSIC (Multiple Signal Classification) Algorithm. Most of the computational power is spent on calculating SVD. My approach is to take ...
3
votes
0answers
102 views

Incorrect Frequency results when using Multiple Signal Classification (MUSIC)

I am using MUSIC (Multiple Signal Classification) to determine Direction Of Arrival (DOA) and frequency of signals impinging on an Antenna Array. I am using a function ...
5
votes
2answers
179 views

How to classify accelerometer data?

I am trying to detect if a car did accelerate or did brake by using the accelerometer of the iPhone. In the figure below I plotted the collected data. (To collect the data the phone was laying flat ...
0
votes
1answer
80 views

Advice on filtering a CW signal for processing

This question is related to my other recent questions. In the last question, I learned that I should filter about 4 * WPM (words per minute) around the carrier frequency if I want to recover Morse ...
2
votes
2answers
521 views

Why do some radio stations still use amplitude instead of frequency modulation?

Why is frequency modulation (FM) not used on the current amplitude modulation (AM) radio stations? The Police have FM 2 way radios that use only 5 kilocycles of modulation. Instead of the current AM ...