# All Questions

16,633 questions
64 views

### Why is noise a power signal?

1. I'm generating a power signal: ...
34 views

### Covariance matrix for sine wave extraction [closed]

we have added five sine waves with different phase and same frequency in matlab. we want to retrieve all the input sine wave back using covariance matrix method. kindly provide the solution for this.
15 views

### Amount of pixel eroded

Is there a definite relation between the kernel size and shape of a morphology change and the amount of pixels added or removed? I have a case where I have a segmented image, and I need to remove x ...
50 views

### Detrend data with no clear secular trend prior to Fourier analysis?

I am completing Fourier analysis on many different time series of sediment particle flux exiting an experimental flume. Data is collected at a resolution of 1 Hz for durations ranging from ~5,000 to ...
36 views

### DFT conjugate of $X^*[k]$, how to prove its formula in terms of $x^*[n]$?

Trying to prove that: $$X^{*}[k] = \sum^{N-1}_{n=0} x^{*}\left((N-n)\right)_N\ W_N^{nk}$$ Where: $$((x))_N \text{ = x modulus N}$$ $$W_{N}^{nk} = e^{-j\ 2\pi / N}$$ So I start out with ...
28 views

### Temporally locating beats in an audio file

Imagine you have a long recording of a guitar player playing an arpeggio at a slow speed. To simplify, assume the tempo is 60 bpm or lower. I want to annotate this recording with the exact moments ...
13 views

### Filter imaging based on the spectrum image

On the left I have the noised spectrum image can we choose which filter to work based on it? For example in the 3rd row it seems that all the energy is concentrated in the middle so we need to "...
23 views

### Detection of Video Quality Using Python

I am getting started with image/video processing. As a start I have a dataset for which the goal is to detect the quality as the video progresses. Based on my readings I think any video under test ...
80 views

### Light Detection and Ranging (LIDAR) Range Bias Compensation with Light Dependent Resistor (LDR)

I have a distance sensor (VL53L0X), which measures the distance to an object. It is placed outside. I currently do 100 measurements in the best available range mode, then I take the median and insert ...
22 views

### Polyphase FIR image downscaling

I recently started designing a Polyphase FIR filter in with a lanczos kernel interpolator to resample an image in Python. The goal is to downscale the image using these methods. However, I think I don'...
40 views

### Sample-rate, filtering, digital-filtering and aliasing

I am strugling with a question that I hope someone can help me with. I am recording single molecule events which I detect is picoampere square deflections. I wish to use as gentle low-pass bessel ...
43 views

### What is the meaning of inverse signal bandwidth?

I have been studying the two ray model in communication systems. The text I'm studying has two signals, $u(t)$, which is Line of Sight and $u(t-t')$, which is the reflected signal. It quotes, ...
5 views

### 1/3 octave analysis and convert dB/Hz to m/s^2 / Hz

I am new to this type of analysis.I have Labview with addon Sound and Vibration and have stuck with my program. I have uff file with vibration data. In this file I have data in m/s^2(t) units. And i ...
6 views

### Corresponding filter in the frequency domain

If we take a 7 by 7 mean filter in the spatial domain, the corresponding filter in the frequency domain is the sinc function? Is there is a list of filter in spatial domain and corresponding function ...
6 views

I understand how overlap-add works for 1-dimensional signals, but I need to do something similar in 2 dimensions. The paper at this link covers the 1D case pretty well (see p29): http://edoc.mpg.de/...
53 views

### Why do DFT frequency buckets need to be divided by sample period?

edit: This is my first post in this community. I'm sure that my downvoter had a good reason to do so, but could someone please comment and tell me how I can better format my question? -- I have a ...
44 views

### Why is the Z-transform so important in digital filters analysis and design? [closed]

Please elaborate on why this mathematical transform can help analyzing as well as designing any type of digital filter.
24 views

### How can I quantify the distortion in a speech signal?

I am working with certain speech enhancement algorithms, for instance to remove stationary noise or impulse noise from a speech signal. Filters such as those can enhance the speech signal, but they ...
32 views

### Low pass filter preserving amplitude

Are there any types of low pass filters that preserve the amplitude and phase? The one that I am aware of, sometimes called an exponentially weighted moving average does neither. First order Low pass ...
36 views

### Nyquist Rate (Sampling Frequency) for ${f}^{2} \left( x, y \right)$

We are given that $f(x,y)$ is highest frequency is $\omega$ what will be the frequency sample rate if we want to restore the function of the form $g(x,y)=f^2(x,y)$ Would it be correct to say that ...
24 views

### Calculating phase of DFT sinewave?

I have been attempting to make a basic, slow, DFT in Matlab and have noticed peculiar behavior that I don't understand. I have been trying to plot the phase of a 100Hz sinewave captured at 250kHz ...
10 views

### Adaptive Clip Limit on CLAHE

I am working on CLAHE algorithm in order to contrast enhancement. I try to find best clip value to get best result image. However, each input image desires different clip value. Therefore, I need an ...
22 views

### Which frequency filter is it?

To which frequency filter the following operator is equivalent? -1 0 -1 0 4 0 -1 0 -1 In the image domain, it is a laplacian rotated by 45 degrees. In the ...
22 views

### Voice classification

I'm working to prepare research article for my project. While preparing for it, I've gone through the topics like Gaussian mixture model and Fourier transform for voice classification problems. I've ...
34 views

### What's the difference between “Discrete Fourier Series” and “Discrete Fourier Transform”? [duplicate]

I look at the equations for DFS (Discrete Fourier Series) and DFT (Discrete Fourier transform) and the only difference I notice is that one has a squiggle above the letter and the other doesn't. The ...
18 views

### Expression related to Tellegen's theorem and signal flow graphs

I'm reading the paper "Signal Flow Graphs-Computer-Aided System Analysis and Sensitivity Calculations" by Arnold Y Lee and my question in about expression/equality (59) in the paper. The expression ...
22 views

### Rotation invariant vs rotation variant

I have a very basic question. We have Rotation invariant filters and filters which are not invariant to rotation. Now let us suppose I want to apply one of these filters. How can I decide which one is ...
48 views

### Is discrete cosine transform differentiable?

Is DCT differentiable? I.e. is d(DCT(x))/dx defined? I've seen a few implementations in automatic differentiation software packages, so I suppose the answer is positive, but I'm still missing a ...
23 views

### What principles to use, in order to create field that will be read by OCR?

I currently have an invoice, where some numbers are written by hand, and I would need to read them automatically. My past experience is that people who write numbers will them write in so many ...
50 views

### Sampling Frequency, Fast Fourier Transform and some strange results in python

So, I have 2 types of signals - Dirac: $\left[ 1,0,0,0,0..NumberOfSamples \right]$ and Gauss (it's sinus * window_gausian). I need to do some operation in ...
93 views

### Why does a higher sampling frequency mess up my bandpass filter?

I was designing a bandpass filter in python using some of the scipy.signal modules. I am plotting the frequency response of my filter to verify that my desired frequency is in the passband. However, ...
23 views

### Quantized error in scatter plots for a hamming windowed LTE signal

I have a time domain signal based on LTE standards. Carrier spacing = 15KHz, Symbols per slot = 6, extended Cyclic Prefix = 512 samples FFT size = 2048, No. of sub carriers = 1200, channel BW = 20MHz, ...
17 views

### How to handle NIR data when using Savgol filter?

I have spectra data of plant leaves i.e coffee. I want to transform the data with the low pass filter... is it advisable to do this? and what are the techniques one can use to preprocess the data
21 views

### Quadrature component - condition on equivalent lowpass signal

I have a question regarding the equivalent lowpass signal $x_{LP}$ of a bandpass signal $x(t)$ and the quadrature component. I'd like to find a condition on $x_{LP}(t)$ and $X_{LP}(f)$ such that the ...
44 views

### Intersymbol Interference

Currently I have generated a ISDN 2B1Q signal and added a random signal to it,then I have designed a lowpass butterworth filter to remove the noise as much possible in MATLAB. My next task is to add ...
10 views

### How to use a context window to segment a whole log Mel-spectrogram (ensuring the same number of segments for all the audios)?

I have several audios with different duration. So I don't know how to ensure the same number N of segments of the audio. I'm trying to implement an existing paper, so it's said that first a Log Mel-...
31 views

### How to normalise data for iterative computation of extrinsic camera matrix?

Hartley & Zisserman defend that data normalisation is an essential step prior to the estimation of geometric image transformations. The reasoning behind this, as stated in their book [1, Section 4....
32 views

### Failed to Get Silence in Audio Streaming

I want to detect silence in audio streaming. I've been following lot of answers from any website and i feel like know how to do that. but i doubt i'm on the right path coz the result doesn't seems ...
22 views

### Why is root square coherence seldom used?

Why most common programming languages used for signal processing (eg Matlab, python) don't have a "root square coherence" function, but only the magnitude squared one? I'm working on a MIMO problem ...
7 views

### Cross-correlation visualization in terms of surface area under graph?

Knowing that Convolution is the total area under the the superimposed two functions, it really help me visualize it. Now I am confused by cross correlation, which is a convulation without the initial ...
24 views

### Resources for learning Sound Processing [closed]

Does anyone know of any resources that explain simply, these are the data objects and variable definitions involved when doing sound processing? I took a class on image processing where we learned ...
67 views

### Highest rate achievable by current DSP and A/D chips?

I'm trying to determine whether an application I have in mind is feasible with currently available DSP technology (DSP chips and ADCs). I want to eliminate an interfering signal using an LMS adaptive ...
48 views

### number of samples and Amplitude accuracy,what's the solution to this problem

I'm colleceting data samples from a device (temporal signal) in order to analyze it with FFT function in MATLAB R2015b,first i get N=4063 data points with (delta_t=0.000015s) so my frequency ...
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29 views

### How to solve signal MFSK or FHSS question (received signal+ noise+jamming)

I'm trying to solve the following: $$A \cos(2\pi f t + \theta_1) + B \cos(2\pi f t + \theta_2) = D\cos(?f?\theta)$$ I just need to know the correct value of D, the value ...