Questions tagged [signal-detection]

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1answer
19 views

Matched filter for recieved RF digital packet by LPF

Im transmitting by cc1350 launchpad microprocessor digital RF Packets, transmitted modulation FSK. bit rate of transmitting is 50Kbouad, frequency of transmitting is 868MHZ . Im sampling the signal(...
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2answers
41 views

filtering my received Signal by LPF

I've received my transmitted signal that I sampled it on 20480000 frequency , transmitted frequency 868MHZ , bitrate 100KHZ , I see the "bits" that Im transmitting in my plot in matlab it ...
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0answers
15 views

Converting Received RF packets to binary file that RF packets sampled by dongle rtl-sdr

Im using #SDR software that I transmit packets from cc1350 launchpad to the air and I want to validate that if those packets are valid or not by checking its CRC. my problem is actually the step to ...
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1answer
41 views

How can I objectively measure train noise from a sound recording?

I have made an audio clip of some local train noise, and run it through a spectral analyser: https://youtu.be/ily4VEoEuSc Here's a screen-capture if you can't view that: As I watch the graph while ...
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0answers
41 views

Detecting complex signal within complex AWGN using Neyman Pearson statistic

I need to construct a Neyman Pearson statistic for detecting a complex signal with known amplitude and unknown phase in additive complex Gaussian noise. My hypotheses are: \begin{align} \mathcal{H}_0 &...
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1answer
29 views

Calculating CRC of my packet [closed]

I'm trying to calculate the crc of my packet, how could I calculate my C of my received packet? packet is transmitted as this patern : preamable | syncword | data | crc attaching photo of my ...
2
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1answer
53 views

finding onset of an impulse signal, basics?

New to signal processing, but making good progress, I think. I have a series of (many) impulses I generated, which will be used as impulse responses to model our church's acoustics, in this time of ...
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0answers
19 views

Threshold Estimation from a Linear FM Pulse Position Modulated signal

I have a signal chain to detect multi channel LFM (Linear Fm - Hann window being applied as shaping filter for the pulses) pulses as shown in picture below. (Numbers in the picture is in Hz., for ...
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1answer
31 views

packet encoder RF packets by using LPF for determining if it's zero or one [closed]

I'm transmitting RF packets with frequency 868MHZ , symbol rate (it's the same as bit rate) is 50KBaud , and Im sampling them by a dongle (fs=20480KHZ) to capture those RF packets, the captured ...
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1answer
40 views

Deciding if the received packet is valid or not valid [closed]

I have sampled RF wireless packets as IQ samples file, those RF packets has patterns like preamable|syncword|data|crc , I'm doing cross correlation with my constant syncword (after I did the ...
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1answer
50 views

Is pitch detection for bass instruments a solved theme?

I would like to know if pitch detection is a solved theme for an instrument like a bass (bass tones). Is it, or there is always a percentage of error rate on the detection?
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1answer
27 views

How to detect a signal while ignoring another signal which is a phase shifted version?

I have a signal coming from a sensor as shown below. This signal has high frequency noise (as can be seen from small fast wiggles) and four regions of interest where distinct spikes can be seen. The ...
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0answers
28 views

How to make noise power estimation on a single tone transmission?

Suppose we have a single tone transmission over a Single Input, Single Output (SISO) channel impaired by Inter-symbol Interference and Additive White Gaussian Noise (AWGN). How to compute the noise ...
0
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1answer
28 views

Advantages and disadvantages of multiplying sparse vector with sparse matrix

Assume I have a sparse vector $x$ whose few values are non-zeros, that vector is multiplied with sparse unitary matrix $Y$ giving $z = Yx$. Are there any advantages of detecting the sparse vector $x$ ...
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0answers
42 views

How to detect offset that changes along time in a signal?

I have an issue that has to do with detrending a signal. First, it seems my signals behaves a little unusual (for me, I think). Some signals starts with a quite large offset, then it seems to ...
2
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1answer
33 views

denoising floor function

Suppose that $y(t) = \lfloor x(t) + \epsilon(t) \rfloor$, where $\epsilon(t)$ is zero mean, independent noise. Is there any techniques on recovering $x(t)$ from $y(t)$?
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21 views

How to identify the frequencies of periodic peak signals in a noisy time series?

Suppose to have two time series with peak signals at different frequencies, like these two: ...
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1answer
79 views

DSP based FMCW radar

I have an SDR receiver I'm interested in making into a FMCW radar. The bandwidth is somewhat narrow as it only samples at 64 MSPS. There is a problem in that without a bunch of embedded programming ...
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0answers
39 views

How to perform signal detection in white noise?

We have a signal $s[n]$, given by the autoregressive model: $$s[n] = as[n−1] + u[n], n = 0, 1, ..., N − 1,$$ where $a$ is a real number and $u[n] \sim \mathcal N(0, 1)$ follows a normal ...
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1answer
34 views

Delays and alignment issues: how to compute the an equalizer delay?

For example, if an equalizer model experiences a delay due to its processing, the equalizer may misinterpret the boundaries between the equalized symbols it outputs and, therefore, return meaningless ...
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1answer
39 views

How can I create a jamming signal for desired frequency?

I am working on GPS interferences and countermeasures. I came across jamming in GPS receivers. So I have a input signal with frequency of 1200 MHz How can I create a jamming signal that can mask ...
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4answers
52 views

Signal analysis: selection of oscillatory parts

I'm trying to analyze the following signal: My aim is to select the high-amlitude oscillation parts limited by the red stars. At the beginning, i have tried to set a threshold and keep only the ...
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3answers
38 views

m-ary antipodal signaling

I know that the error probability for binary antipodal signaling is $Q(\sqrt{2E_b/N_0})$ with $Q$ the tail function. I was wondering if when used in a m-ary scheme how the probability error would ...
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0answers
10 views

Noise Temperature for AsiaSat 5

So I am working on AsiaSat 5 G/T. How to calculate Noise Temperature for Antenna I derived Gain at receiver antenna. Now I need to calculate for Noise Temperature to get G/T. how can I calculate ...
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1answer
28 views

Identify if a Specific Edge Pixel Belongs to Horizontal, Vertical or Diagonal Edge Line

I have a code below that identifies the edge of the text image. Input image is: Output display is: I want to select random points near the edge border of the text. I was thinking to identify if the ...
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1answer
37 views

What is full scale?

I read the Wikipedia documentation and it's not clear to me what is the full scale concept. What is the meaning of changing the full scale? How I can preserve data in that scale?
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0answers
57 views

GPS Acquisition Graphs [closed]

I am trying to generate GPS Acquisition signals using frequency code phase search acquisition. I generated C/A gold codes and digitised at 16.368e6 MHz(sampling frequency) I generated carrier signals ...
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1answer
19 views

Please clarify the mandatory condition on Vestigial Sideband Modulation filter?

In VSB filter we have the Transfer function condition as $H(F-F_c)+H(F+F_c)=1$ So can we accept that for the range of $F$ in $(F-df,F_c)$ we have $H(F)$ and for $(F_c,F+dF)$ we have $A-H(-F)$ where $...
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2answers
46 views

Coherent detection in radar and radio signals

Coherent demodulation\detection is usually done via matched filtering in RF signal processing. In radar signals, coherent integration can be done if the phases of the returns are known. In terms of ...
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1answer
50 views

Loop Bandwidth for Carrier Demodulation loop

I am trying to implement a simple MATLAB model for the demodulators for phase modulated signals (PSK) used in communication systems. For the detection of the phase modulated output (PM out in the ...
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3answers
137 views

Understanding the Difference Between MAP Estimation and ML Estimation

There are a number of possible criteria to use in making decisions. Can someone elaborate on the difference between ML and MAP for a sequence of BPSK symbols impaired by Gaussian noise ?
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2answers
57 views

Typical shape detection algorithms

Here is my target, given a set of consecutive discrete 1-d data points within a window. I want to know whether there are good algorithms to detect certain typical shapes of the signal in the window. ...
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1answer
55 views

Detect when signal starts oscillating

I have a signal which consists of oscillations riding on square waves as shown in the image below. I wish to detect the time at which oscillatory events occur (as shown by the red star). Each square ...
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2answers
63 views

If I can make a call to another city, why does wifi only reach 50 meters?

What makes it possible for me to communicate with someone in another city when my phone can only reach the modem / wifi networks that are within 50 meters? The signal may be sent between multiple ...
1
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1answer
68 views

Projecting a vector to another to detect the sparse values of such vector

Assuming we have sparse vector of length $N$ such as $X = [0,1,0,-1,0,1,1,0]$ which has some non-zeros values. The vector $x = iFFT(X)$ is convoluted with another vector $h$ resluting $y = h*x$. ...
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0answers
16 views

How to reliably identify the starting point of multiple instances of a noisy signal?

I have collected data from a person performing the same action for 10 iterations. As shown in the figure, signals from all iterations look very similar, but contain some unwanted noise in some ...
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1answer
31 views

How do I find variance from the PSD of a stochastic process?

I have a time series that consists of noise and a signal, shown here windowed and Wiener filtered: and the PSD of just the noise (used in filtering): I want to find the variance of the noise using ...
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0answers
28 views

Energy Detection Sensitivity Comparison

In the area of broadband spectrum sensing, there are multiple methods used to detect energy. Two common methods are: Energy detection in the time domain (matlab example) Spectrogram (often defined by ...
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2answers
63 views

Probability of error for detection problem

Let $X \in \mathbb{R}^N$ and $Z \sim \mathcal{N}(0, \sigma^2 I)$ be random vectors. $Y = X + Z$ $X$ can be either $a_0 \in \mathbb{R}^N$ or $a_1\in \mathbb{R}^N$ with equal probability. So the ...
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0answers
16 views

Right approach for activity classification based on EMG signal?

I want to train a classifier that is able to identify different activities based on EMG data that is sampled at 41Hz with 8 channels, I read this paper that summarizes a lot of different approaches to ...
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3answers
87 views

best technique to remove noise from bio signal data

I'm still learning about signal processing so sorry if this is an intro problem. I want to remove noise from the following data so I can separate each wave and run analysis on it. The data is sampled ...
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0answers
37 views

Obtain SIB1 messages from CPRI the captured DL IQ data

I am a beginner in the signal processing, and I know some python and I have a project I'm working on which is about Obtaining SIB1 messages from CPRI the captured DL IQ data. I have captured some DL ...
0
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0answers
36 views

Strange signals in wifi channel

I am currently working with a USRP B200 mini-i to receive 802.11 signals from various usb wifi devices. When sending packets with the USB device over a channel, lets say 2.412GHz, i can't really see ...
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2answers
68 views

Can an audio recording tell whether it is made in a large or small room?

The conversation of one or more people will be analyzed. I think need to look for something similar to reverberation or echo in an audio signal. How can this be implemented? Update: small room is ...
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1answer
35 views

Synchronize device to audio stream - Approach

I am working on a device which's actions should be synchronized to the audio played. The audio stream is known in beforehand and can be altered to contain signals for the synchronization. But the ...
0
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1answer
43 views

Proper HW circuit to decode PWM signal using Arduino Mini

I want to properly connect a Radio Control Receiver signal to a Arduino Pro Mini, Pin 11 so I can detect the 1 ms to 2 ms PWM signal. I calculate a value of 220 ohms will limit the circuit current to ...
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0answers
22 views

Understanding shift in Q values?

Can any one help me understand why there is a shift in Q values? It seems there is a DC offset/bias. How do I remove it or set it accordingly to make it equal to the I values/waveform? I am using a ...
0
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1answer
45 views

What is the type of each 4 different noise signals that are shown below?

Dear signal processing experts, I am looking at four different noise signals.I got them in a time domain and they are different. I went to the frequency domain and found the fft for all four signals....
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2answers
102 views

Pulse Doppler Radar: time delay in down conversion

My understanding of Pulse Doppler Radar is the system measures Time Of Flight for the pulse. My confusion is that during the down conversion process prior to ADC the lowpass filter causes some time ...
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1answer
51 views

Coherent Radar — How do we justify it?

How can we justify doing coherent radar when the phase of the return is unknown? For instance, after a reflection, assuming a stationary target, we should get something akin to: $$ x_{rx}(t) = |\...

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