# All Questions

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### How to apply a Butterworth filter to data of varying sample rate?

I am trying to apply a Butterworth bandpass filter to accelerometer data of my smartphone. However, the accelerometer samples I receive do not come at regular intervals. Sample frequency varies ...
19 views

### Matlab: is a highpass filter what I want, to obtain my required spectrogram? How do I design/apply this? (pic included)

The axes are wrong in the spectrogram. I have an audio wav file, and I know the sampling rate. this is read into the audioData variable. The audio is 1 channel. selected window length I believe (can't ...
8 views

### Efficiently compute bases functions of the signal

Let there be 4 1D signals such that \begin{cases} x(t)=4\sin(10\pi t) \\ y(t)=8\cos(20\pi t) \\ z(t)=16\sin(30\pi t) \\ m(t)=x(t) +y(t)-z(t) \end{cases} Is there a way to compute ...
9 views

### SFBC Alamouti Scheme LTE

That a 2$\times$1 Alamouti SFBC is referred to as a rate 1 code, two symbols are sent over two adjacent subcarriers. Reference: Fundamentals of LTE Book. This question is regarding this SFBC encoder ...
19 views

### Fixing drift in a recursive fixed point filter

I'm implementing a 80-72-64-48 multi pass moving average filter for a embedded system in C and in fixed point. The implementation is a circular buffer where i'm keeping a running sum and calculating ...
15 views

### How to calculate Dot Pitch for a device?

Okay I am trying to figure out how to calculate the dot pitch for a monitor. For example a 14inch monitor with a display area of 9.875inch and a height of 7.125inch and a diagonal 12.25inch with a ...
22 views

### Filtering Random Signal

My question is easy one actually. First, I generate a random signal using randn() function of MATLAB like this: Then, I design a FIR filter of order 200 of ...
12 views

### differences between 2D and 3D Medical Images

i have two questions: 1)what is the difference between 2D and 3D medical images? 2)assume i have a 2D image and for example it contains 1000 ROIs. each ROI is a matrix and we can convert it to a ...
134 views

### Is it only me or matlab's periodogram's function is confusing?

I am really confused with matlab's periodogram. First of all, it says in the documentation that its unit is "dB per unit frequency". What does that really mean? I just don't quite get it. Second of ...
11 views

### how can we apply dirichlet power spectrum and dirichlet transform in signal processing? and how Dirichlet work in signal? [on hold]

Currently, I'm doing research on vibration signal. I've extracted some features just by using simple statistical features. I directly extract the features from time and frequency domain. Now, my ...
23 views

### Can we decompose a correlated random variable into correlated plus uncorrelated?

Assume a random sequence $Y_k = X_k \cdot H_k + W_k$ where $X_k$ is a deterministic quantity, $H_k$ is a correlated random sequence, $W_k$ is Additive White Gaussian random sequence. Can we ...
17 views

### Distance Transformation in image processing

What is the exact purpose of distance transformation in image restoration. Is it a way to restore or only a step towards restoration of a blur image?
35 views

### FIR design using firpm (Parks-Mclellan)

Can you please help me with some ideas on how to implement an FIR filter in Matlab using Parks-Mclellan algorithm? My specifications are the passband cut-off frequency, the transition bandwidth. The ...
25 views

### ISI Nyquist criterion and spectral efficiency

While reading Bernard Sklar's Digital Communications book I've got confused with ISI Nyquist criterion (not Nyquist rate criterion). There is stated (Sklar, 3.3 section) for symbol rate $R_s$ minimum ...
69 views

### Fourier Transform of a Distcrete Sequence Periodic?

Why do we say that the Fourier transform of a discrete sequence is continuous, for example here Fourier transform converts every discrete sequence in continuous spectrumMy first question is for the ...
25 views

### the significance of these two successive bumps

Suppose there is a sin curve with amplitude A, which is I=ASin(t)* . If we detect two small bumps near two successive peaks of the ...
19 views

### cause of adaptive threshold poor result

I try to run text cleaning process based on the camera captured image. By using OpenCV adaptive threshold method with parameter ...
30 views

### What is the cause of slow roll off of windowed filters

Exactly why using the of windowing function, such as Hamming or Blackman, causes a slower transition to stop band? Everywhere it is mentioned just as an obvious fact that this happens but I haven't ...
6 views

### ZCR and Energy features for VOT problem?

Can I use Zero Crossing Rate (ZCR) and Energy features for a VOT detection problem? Is it the same as in Voiced/Unvoiced classification problem? or are there any differences? Thank you in advance ...
5 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 ...
39 views

### How does a matched filter know about input signal beforehand?

I know that a matched filter at time t0 is just the input signal reversed in time about that time. But how does the filter know about input signal. Received signal is transmitted signal plus the noise ...
26 views

### Filter signal1 from evolving frequency response of signal2

I'm a composer (of music) starting out with signal processing. I'm also reasonably proficient in C at this point. I'm not even sure if what I'm trying to do is possible, because I can't yet find an ...
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### solving a 12-point DFT [on hold]

Some values for the 12-point DFT, X12(k), for a length-4 real sequence x[n] are given in the table below ...
112 views

### Finding the Harmonics contained in an Image?

I am beginer in image processing. Any signal whether it is 1D,2D or any multidimensional signal can be represented using combination of number of sine and cosine wavesforms (harmonics). Similerly any ...
33 views

### Spectral analysis of a time series with missing data points

I use a PC to record time series of some physical property. The problem is that, for some reason, I did not record the time series as a whole, rather I record first segment, then second, third, etc. ...
48 views

### How do I interpolate between bins on an FFT in python?

I have four frequency peaks, which I have after applying FFT. Now I want to know precise values of these frequency peaks. there are different interpolation methods. How can I use this method of ...