# All Questions

16,755 questions
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### Plotting the frequency response of a FIR filter

I am trying to figure out the mechanics of plotting the frequency response of a FIR filter. For example, I have used an algorithm (Parks-McClellan), to generate a low pass FIR filter with an even ...
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### Omega-K algorithm implementation for synthetic aperture radar

I have been trying to develop Omega-k algorithm for SAR image formation. I am using the equations from chapter 8 in digital processing of Synthetic Aperture Radar data by Cumming and Wong. The steps I ...
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### What is the physical meaning of the cross-spectrum of two signals measured at two locations and different moment?

I am working with steady state pressure field measurement where sound pressure at multiple locations in the field needs to be measured. In my case, more than one microphone existing in the field at ...
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### Calculating pre-history of recursive filter from state space representation when optimising for initial z

For a recursive filter, suppose a set of $b$ and $a$ coefficients have been calculated. Assume a state-space representation for which an initial set of $z$-values have also been calculated as in ...
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### Spectrogram of a single tone complex signal has two dark lines?

I am trying to plot the spectrogram of a complex signal I generated. I have written code to generate this signal and plot the spectrogram. It works. However I see that there are two dark lines present ...
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### SRF-PLL discretization problem

So I've been working on how to digitally implement a static reference frame PLL (SRF-PLL), which is a quite popular PLL used for extracting three-phase grid angle. This PLL works by using the DQ0 ...
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### Find the noise settings to reproduce it

I work on images that contain shot noise (Poisson) acquired from a microscop. On few images, I have a "flat" zone that is supposed to have the exact same intensity, but it's not because of the noise. ...
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### BER performance of a space-time code over Rayleigh channel model

For a given space-time code, and in general terms, how would one proceed in the evaluation of the BER performance of this code ? In order to be more clear, say i have 16 code matrices(who's elements ...
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### I am trying to convert a signal into another unit, but the error keeps increasing during each iteration

I have a signal, A, and I want to convert it into another unit by using a formula: $$s_i = \frac{(1+x_i)}{(1-x_i)}\cdot s_{i-1}$$ where $x_i$ is each sample of ...
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### When we set a State vector during bayesian process, can we use only velocity or location?

When we use a bayesian framework, We firstly set a state. The state is what we want to know.. At this time, Can we use just location or velocity like belows? (X is state vector) For example, X = (x,...
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### How do I filter out the specific components at 20MHz, in this figure?

I used the filter builder (lowpass) , to cut off the frequency at 0.5 MHz, and thus used a stopband of 0.1pi, and a passband of 0.0125pi. (Sampling Frequency= 80MHz). However, the output was still ...
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### Kalman Filter State Covariance Matrix

If I have a discrete time process model of the form: $$x_{k+1} = x_{k} + v_{k}\cos(\theta_{k})dt$$ $$y_{k+1} = y_{k} + v_{k}\sin(\theta_{k})dt$$ $$v_{k+1} = v_{k}$$ $$\theta_{k+1} = \theta_{k}$$ ...
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### How to calculate SNR with sample noise and noisy signal only

I want to calculate the SNR for a speech signal recorded within a noisy environment. I also sampled purely the noise within the environment. The SNR is based on the ratio of power of clean signal ...
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### How to detect algebraic loop in a system

I came across a system (screen below) that looks like it should result in a algebraic loop, but when writing the equations using the Z-transform, it obviously does not (calculation below too). But I ...
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### Plot Frequency Spectrum of Binary Sequence in Matlab

I am new to Matlab and I am trying to implement a section of a published paper, the basic idea of the part that i am implementing is to show the frequency spectrum of camera aperture. The shutter ...
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### Aliasing from downsampling and Nyquist

In a book Conceptual Wavelets in Digital Signal Processing by Lee Fugal 2009 on page 246 the author talks about aliasing present in DWT subbands due to downsampling by 2 and states: Recall from DSP ...
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### Proof of time-invariance of discrete time system

I'm looking at this discrete time system: y[n] − 4y[n−1] + 4y[n−2] = 20x[n] + 10x[n−1] how do I proof that it time-invariance? Thanks!
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### IIR filter with circular buffer - Arduino

I am trying to implement a butterworth lowpass filter with a circular buffer. The code below does not filter as intended and I am not really able to understand what is wrong. Any suggestion? ...
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### How to express STFT and ISTFT as a 1d convolution and 1d deconvolution in tensorflow/keras

I'm trying to implement this paper in tensorflow and keras. At the end of section 3 it says. ...
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### Separability vs. Resolution - Synonymous terms?

In terms of discrete representation of a variable, let's say time measurements in absolute values in [seconds], is there a difference between separability and resolution? When do speak of either ...
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### Limiter, compressor, AGC, dynamics processor?

What are the primary differences between the usage or definitions of the terms “AGC”, “compressor”, “limiter”, and dynamics processor? They all seem to be forms of playing with gain knobs.
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### Why sampling a periodic signal doesn't yield a periodic discrete signal?

I've been studying Signals and systems lately and I've came across a bullet point in a slide that claims "The uniform sampling of a periodic continuous-time signal may not be periodic!". Can someone ...