# All Questions

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### Formula for S/N ratio

I'm trying to calculate the energy balance of satellite link, I know that: $$P_t=100 {\rm\ W,}$$ $$G_t =206340 {\rm\ W/W,}$$ $$G_r=6650 {\rm\ W/W,}$$ $$L_{fs} = 5,502 \times 10^{20} {\rm\ W/W.}$$ I ...
11 views

### Indexing problem with using FFT convolution to remove echo

I've been using a very basic kernel to remove a known echo from a signal via convolution in the time domain e.g assuming a signal contains a delay of 5 samples ...
10 views

### What do the Contour Levels Produced by Matlab Function Contourc Represent

I have been trying to understand what the contour levels are. As far as I understand a contour of the function $Z(x,y)$ is a set of points in the $(x,y)$ plane, such that $Z(x,y)$ is fixed at some ...
14 views

### what are the hot area of searching in FMBC and Massive MIMO

I'd like to ask about Massive MIMO, and FBMC .. what are the hot areas of searching in these two topics ? I mean for example in OFDM, it's needed to check the ISI, ICI and channel estimation and so ...
13 views

### upconverting a kHz/MHz signal to GHz

I want to know how in practice we can take a kHz/MHz signal to a GHz band? Suppose we have an FSK modulated signal at around 300 kHz (or 20 MHz). I want to take it to 3.5 GHz, so about 3499700 kHz ...
4 views

### DTW MFCC pronunciation similarity

There are two wav files with the same word recorded. To compare this, we extracted the wav file pcm, MFCC (Mel frequency factor) and obtained the Euclidean distance value through DTW. (1) and (2) are ...
15 views

### Finding the fundamental period by using four elementary operations (+,-,x,/)

The idea is to find the fundamental period of any periodic and bounded signal. This is all that we know about the signal. Nothing else. Only allowed operations are: $+,-,\times , \div$. We can also ...
14 views

### Frequency hopping signal bandwidth

I am confused about how to calculate the signal BW in a frequency hopping system, is the signal BW a function of the frequency separation and the number of frequencies used or is the hopping rate ...
15 views

### Single frequency missing in time domain effect

How to explain effect of a missing frequency in time domain ? As we know it is simple task when we talk about frequency domain and missing a frequency component in there (in spectrum).What about time ...
36 views

### Convolution Strategy

I would like your help on a theoretical question regarding convolution. The point is to design a faster discrete-time convolution operator functioning on one-dimensional space so that y[n] = x[n] * h[...
15 views

### Decimation for upsampling and downsampling

Prologue of the problem I have a dataset of ADLs (Activities of Daily Living) - MobiFall. It's been stated that accelerometer sampling frequency was 87Hz, orientation and gyroscope were 200Hz. But in ...
22 views

### What reference power should I use?

My professor asked me to convert following powers into decibels: 15W, 25W, 33W, 450mW, 24MW, 44 GW,120pW. I know that decibels are about ratio power/reference_power. I don't have reference power ...
28 views

### Ideal sampling of audio signals-Periodic spectrum

When applying ideal sampling on audio singals, why is the spectrum periodic ?
15 views

### DFT as an Orthogonal Basis Change

In one of the homeworks that I am dealing with for Linear Systems course, I have encountered with such a statement: Consider $\mathbb{C}^N$ the vector space of N dimensional complex vectors. We can ...
19 views

### Unexpected results from DTW comparing two MFCC feature vectors

I'm trying to compare two people's pronunciations of the same sentence: "no signal." I ran the following code on said pronunciations and the DTW distance output was 8.4. However, when I used one of ...
23 views

### Why do we substract a background image and not divide it?

Subtracting a background image for background correction is the standard way of doing background correction to obtain the foreground. I am wondering if there are situations, where it would make sense ...
251 views

### Practical book in C [duplicate]

Is there any practical “go to” book that demonstrates the main dsp methods for time series written in C for practical applications? (Doesn’t have to be for hardware, but for any raw data such as ...
7 views

### Log likelihood ratio values

How to compute/calculate the log likelihood ratio values from iq's of a GMSK signal
31 views

### How to compare multiple polynomials in MATLAB?

I am trying to fit a second order polynomial to various curves on a binary image using MATLAB polyfit function.There are many such curves on the image, and the ...
33 views

### OFDM RF signal waveform

From the Wikipedia article: "An inverse FFT is computed on each set of symbols, giving a set of complex time-domain samples. These samples are then quadrature-mixed to passband in the standard way. ...
18 views

### Question based on scaling the FFT for obtaining PSD

Following is the code given in MATLAB's site to estimate PSD using FFT. ...
9 views

### FFT and correlation between two signals for word detection

I have a task where I am supposed to make a python script for word recognition and I am not allowed to use any high order python commands without the fft and ifft command. The audio signal is ...
56 views

### What is Faster Than Nyquist signaling?

Faster than Nyquist signaling is used to improve the spectral efficiency by reducing the time spacing (relaxing the orthogonality constraint) to pack more data in the same channel while tolerating a ...
29 views

### Signal reconstruction from sampled signal?

Can we construct exact analog signal at receiver as same as source from the sampled signal????
33 views

### Correlation of a signal

I have one sample for a signal. This sample is a vector of length 384. I need to calculate the correlation matrix for this signal,So I need many samples for the same signal. How can i generate these ...
9 views

### Difference between morphological gradient and derivative of 1-D signal

What is the difference(s) between morphological gradient and derivative of 1-D signal (x(t))? Thanks in advance.
15 views

### “Image Processing” [on hold]

I'm an Italian student. I'm studying Gnu Radio and I would like to upload a photo, can I upload it with "file image source" or other blocks? I need to make FFT of an a image. -> image 2D Thank you ...
753 views

### Why should an image be blurred using a Gaussian Kernel before downsampling?

I recently read that before downsampling an image, it should be blurred using a Gaussian Kernel. This way, the downsampled image is better than just picking a single pixel out of a NxN block or ...
22 views

### Implementing real-time signal processing filters

I’m currently working on my capstone for school, and I’m looking for some guidance/tips when it comes to real-time filtering. The nature of the project is to monitor breathing patterns, send the ...
23 views

### how to create a harmonic mask from fundamental frequency?

Using an algorithm that gives the fundamental frequency across time, example https://www.mathworks.com/help/audio/ref/pitch.html (or some other one?) how would I then use that, to create a harmonic ...
14 views

### Multirate System - reduce to QMF

I have the following digital system shown below, the problem is to first redraw the schematic using multirate and single rate blocks. I understand that to split into even samples, decimate x[n] by two ...
13 views

### What is an intuitive understanding of the difference between the minimum required bandwidth and actual bandwidth?

When using for example, polar signaling of full width rectangular pulses, the bandwidth is equal to the pulse rate $Rb$, which is also the bit rate. $B=R_b$ for full width rectangular pulses. But ...
21 views

34 views

### Real time background noise reduction or removal

I am trying to build a real time simple audio recognition that can recognize few keywords. Following this tensor flow tutorial i was able to train a simple neural network. Currently the signal flow ...
25 views

### Find identical audio signal

I have a long audio file (in wav) and a short audio file (in wav) that has been copied from the long file. Now I need to find the correct location where the short signal has been copied from. I tried ...
19 views

### Equalizing a temporal sound signal with a convolution

This question is more or less the following of a previous question. The aim is to equalize some sounds signals. By equalizing, I mean increasing or decreasing some frequency ranges, a bit like an ...
31 views

### Identify random repetitive patterns

Forgive me if it’s too basic, I finish engineering a while ago. Given any time series, not periodic, I would like to find any repetitive pattern that is distinct (by some given measurement) and is ...
44 views

### Why does SNR have an impact on the bit rate?

I have some confusion regarding the impact of SNR on the bit rate. For example, if I have a QPSK-OFDM system, then my bit rate will be 2bits mutiplied by the number of sub-carriers of the OFDM ...
57 views

### Basic confusion about the DFT and convolution

I am learning DSP (with Digital Images) and I have some elementary confusion about the convolution between two discrete periodic signals. Specifically, I have learnt that when filtering an image, we ...
25 views

### Frequency component not filtered properly

Does frequency component other than wanted signal present in output if yes than why it not disturb original signal??? I think all practical filter response are not ideal so all frequency component ...

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