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# Questions tagged [interference]

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### How to relate a section of a PSD plot back to the original complex numbers IQ or remove part of a signal from a spectrum with python-signal excision?

I have data coming off an software defined radio, I want to remove a certain signal(interference) from a spectrum new to DSP. I am using python. the signal comes in as an array of complex numbers (...
1 vote
58 views

### How can it be possible that I hear people voice from my computer speaker?

I searched on web and apparently can be due to truck drivers communicating at CB band which is around 20MHz. And apparently this communication may interference with the frequencies used by computer's ...
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### What is the most used signal for basic pulse?

My professor said that: in order to avoid interferences/harmonics caused by the nature of the square wave g(t) (sinc will have these secondary lobes), it's better to change the basic pulse g(t) to ...
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### Since harmonics only generate at multiples of the center freq, is it for this reason that the left part of a FT (like sinc) has no physical meaning?

If we have a rectangular pulse function, we know that after a Fourier transform we obtain a sinc: We know that the left part (negative frequencies) has no physical meaning and it's just specular. It'...
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### Tracking period of quasi-periodic transient type signal in strong non-stationary interference

Consider a desired (pink) signal as well as its observation in heavy, non-stationary interference (green, this is the desired signal plus interference). As seen in the plot, the interference can also ...
• 489
56 views

### Hilbert Transform matches signal rather than envelope

I have an interferogram of a white LED. I am trying to extract the envelope of the signal. Shown is the interferogram, and the absolute value of the Hilbert Transform of the interferogram. I used <...
1 vote
136 views

### Fractionally spaced equalizer - LMS algorithm

I am doing a project in MATLAB about the fractionally spaced equalizer. The method that i have chosen to update the tap weight coefficients is the LMS algorithm. Here is the block scheme that i have ...
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### How to explain the meaning of the intersection in a Fourier series representation of periodic signals?

I saw a piece of code on github which transforms the planetary movement into the Fourier wave function. These circles are given by the $x$ and $y$ ordinates: $x=\cos (\omega t)$, $y=\sin (\omega t)$, ...
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### Interference between 121.5Mhz and 124.5Mhz

I'm new to Software Defined Radios and trying to find out if powerful signals are a cause of my own interference, a poor setup, or just a lot of traffic. I'm using a HackRF One with an ANT500 antenna. ...
• 101
1 vote
195 views

### Simulating RF interference (noise) to captured RF signals

I have carried out an approach to clean my RF signal captured in order to perform classification on a set of devices. However, a further extension to this study I aim to achieve is to evaluate the ...
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### Can I still use match filter (eg.RCC)at rx when there is none at tx? Can it help with ISI?

As the transmitter is restricted to size and power considerations, there is no way to apply a SRRC filter at tx side. Can I just put a RC(raised cosine filter) at the rx side to alleviate ISI?
1 vote
1k views

### Getting envelope of noisy signal

I am analyzing some interferometry data and have a time signal that looks like this: Our temporal resolution is unfortunately not enough to resolve the fringes. I need to get the upper envelope of ...
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1 vote
529 views

### The raised cosine spectrum and Nyquist's criterion for zero ISI

For the past hour, I've been trying to understand what the book is trying to say here: This is Communication Systems, 5th Edition by Simon Haykin. We know that the Nyquist criterion is I'm unable to ...
• 267
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### Higher Spectral Efficiency with Frequency Domain Equivalent of Partial Response Signaling?

In other recent posts such as this one, I detailed partial response signaling common to GMSK where a known inter-symbol interference (ISI) is intentionally introduced in the time domain at the benefit ...
• 53.1k
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### gmsk modulation: ISI reseach

I reseach gmsk modulation with linear approximation + laurent decomposition. In the answere to the my previous post, MR Boschen: L is the overlap of successive symbols as L is given in symbol ...
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### Why is there fear of interference between 5G and airline altimeter C-band?

The C-band frequency range to be used for the 5G-advanced rollout is the US is in the 3.7-3.98 GHz range. Whereas altimeters operate in the 4.2-4.4 GHz range. Is there any genuine reason to worry ...
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### FFT on a specific part of an image [python]

I'm currently working on a project where I have to analyse an interferogram. Instead of doing an FFT on the whole image I'd like to focus only on a small part of it (one fringe) is it possible to ...
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### Related to successive interference cancellation?

I am trying to understand the following query: " Is it necessary to do channel estimation to perform successive interference cancellation at the receiver operating over fading channel" Any ...
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54 views

### Alg for identifying any temporal interfering signal

I'm a little bit on a loss at my search for an algorithm due to audio signals. I'm a sw-engineer with some basis knowledge in math here and there, know how to build and use FFT etc. but with no prof ...
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137 views

### The power of signal processing when faced with hardware constraints

I am currently studying interferometry, but I have only just begun studying signal processing. I want to better understand the effect signal processing can have in maximising signal detection from ...
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### How to remove power line interference?

I have a couple of datasets that show a peak around the 50-60 Hz range (mostly around 55Hz and in some cases at their harmonics i.e. 100-120Hz.) In some datasets the spike is significant in comparison ...
101 views

### Detecting and removing interferences from a signal

I am using MATLAB in order to denoise and remove interferences on a signal. I used wdenoise to denoise my signal which works by setting a threshold (for example ...
1 vote
83 views

### Interference fringes movement analysis

I have searched Stackexchange forums for ideas, but could not find anything useful for me. I am registering real-time stability of the He-Ne laser interferometer by analyzing interference fringe ...
345 views

### Filter for DC component in FFT2 of image

I am trying to get the main frequency of the Fourier Transform of the image below, which is the intereference pattern detected by a CMOS sensor. When I apply fft2, I got the DC peak at 0 frequency, ...
262 views

### Fringe movement analysis to extract displacement

I am using a Michelson interferometer with the interferogram recorded on a CMOS sensor. I have taken a video of the fringes moving when a displacement of 50 $\mu m$ is imposed to one of the mirrors. ...
1 vote
83 views

### Can the intelligence message of an FM signal be cross-modulated to another center frequency due to non-linearities?

Can the intelligence message of an FM signal be cross-modulated to a a different frequency by non-linearities, but with the FM modulating message remaining (relatively) intact on the new frequency? ...
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### How to compute total interference power at receiver antenna

I would like to know what is the proper way to sum interferences. I have, for example, let say 0.4 mW, 0.035 mW and 0.2 mW are those interferences. Do I have to sum them resulting 0.635 mW or make a ...
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### To implement successive interference cancellation (SIC) process, should the receiver know the power allocated to each symbol?

My question is as follows: To implement successive interference cancellation (SIC) process in downlink non-orthogonal multiple access (NOMA), should receivers know all power allocated to each symbol? ...
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### SINR is 3-tap zero forcing filter

I have a following toy example: received signal: $y[n] = x[n] - x[n-1] + z[n]$ and with $\text{Pr}(x[n]=1)=0.3=\text{Pr}(x[n]=-1)$ and $\text{Pr}(x[n]=0)=0.4$ and $z[n]$ is a Gaussian distribution. I ...
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### 5G NR Network Collision Avoidance

I'm looking for a technical explanation or a specification that explains exactly how 5G NR collision avoidance will work. I was watching a talk from the Mobile World Conference in Shanghai two years ...
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### Interference Distribution Assumption in NOMA IoT Scenario

I am assuming a NOMA IoT Uplink scenario, which is interference marred. I have to ascertain the SINR at the Access Point (AP) for the NOMA users. A sub-channel is allocated to various users and ...
25 views

### simulating directional interference to evaluate model performance

I have a model for audio processing. The model receives as input, a source, convolved with a room impulse response (RIR). I would like to test the performance of the model against inputs containing ...
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### Interference in decibles

A is transmitting a signal to point B . But in this process A is creating an interference at point C. So if the distance between point A and point C decreases the interference will increase. My ...
1 vote
55 views

### What kind of signal reppresents this Power Spectral Density?

I'm sampling 8 bioelectric signals with a embedded board which use an 8-channels ADC (AD7175-8). My sampling rate for every single channel is about 6250 Hz. When move the analysis in the frequency ...
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110 views

### Equalizers with low data rate systems

In case of using equalizers with ZigBee systems, what type of fading does the channel show, flat or frequency selective, fast or slow? Is the inter-symbol interference (ISI) problem encountered in ...
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1 vote
758 views

### CFAR Detectors and Interference

Constant False Alarm Rate (CFAR) is an automatic thresholding technique. It's situated after the FFT processing in other to detect target peak. This probability of detection depends on clutter and ...
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1 vote
115 views

### Is there a situation when maximizing SNR doesn't also maximize probability of detection?

The problem I'm working on is signal detection of a radar signal, but I suspect this problem shows up in many different branches of signal processing. Background: From [1], the factor $I_f$, by ...
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1 vote
1k views

### Inter Symbol Interference (ISI) / Equalization in Digital Signal Processing

I am studying the OFDM system and before to start I have decided to study the main concepts of modulation. And I have spent yet a lot of time to understand the concept of an equalization to reduce ISI....
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### Ultrasonic Interference with Electromagnetic Waves?

I am currently working on ultrasonic frequencies (20 kHz-60 kHz). According to a news snippet I found: The state government has also tried employing ultrasonic guns that can scare monkeys away and ...
199 views

### how to eliminate interference in the same center frequency

I'm trying to receive an ASK signal in the 433 MHz center frequency with a bandwidth of 100KHz. I'm using a CC1101 transceiver connected to a Raspberry Pi GPIO ports. However, there is an intermittent ...
101 views

### how to guess what the interference source it could be

At work, we are in an industrial area, and there is always a signal that I receive inside my office which interferences with my tests. This signal is in the 433 MHz and when I see the spectrum, ...
38 views

### Is there some literature to understand finite state ISI channel?

I am trying to understand channels with memory, where the state of the channel gives the past input information. I want to delve further into capacity for channels with ISI. I came across a ...
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### Cross-correlation, sharp peak at 0?

First of all, I have to stress that I am not a professional of coding, no more than a professional of signal processing. I am a chemist that happen to be working on a project involving both. So in ...
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