A discrete signal or discrete-time signal is a time series consisting of a sequence of quantities.
0
votes
0answers
12 views
How to display digital audio signal from sound card
If I understood correctly, the sound card in a PC, changes the analogue signals of sound frequency to digital signals for audio processing. I am a C++, JAVA programmer, albeit a beginner one, and I ...
-1
votes
0answers
33 views
Calculating the Norm of Each Sample of the DFT Trasform
Given a discrete signal $ \left\{ x[n] \right\}_{n=0}^{N-1} $ and its Discrete Fourier Transform $ X[k] = DFT \left\{ x[n] \right\}[k] $.
I'd like to effectively compute the norm of each sample of ...
0
votes
0answers
29 views
How to combine low and high frequencies of two images in Matlab
I would like to combine two images A and B in the following way:
1) I want to take a Fourier transform of both of them
2) For image A I want to apply a weighted filter, which gives more emphasis for ...
-2
votes
0answers
29 views
using different pulse shapings in ofdm [closed]
Hi I have simulated and ofdm system with rectangular pulse but I have prolems how to simulate it with other pulse shapings. could any one help, please? I want to compare the bit error rate for ...
3
votes
1answer
45 views
Fitting fixed number of complex exponentials to complex signal
I have a complex data series, and I would like to fit a fixed number (in this case, two) of complex exponentials of the form $Ae^{jBn}$, where A, B are complex. Not interested in the phase (i.e. arg ...
0
votes
1answer
36 views
How to determine the window size and weights in Weighted Moving Average (WMA), given desired cut-off frequency?
I am trying to smooth my discrete-time data points using the method of WMA.
Currently, I am using n as the window size and the weight array, ...
0
votes
3answers
72 views
Peaking Equalizer
I'm making peaking equalizer in C# using NAudio (EQ-Cookbook). Can anybody tell me what is wrong with this code? It gives me noise.
Sliders
...
2
votes
0answers
44 views
A good Digital Image Processing environment
i'm looking for a free/opensource solution for digital image processing with reasonable performances processing quite large images (e.g. actual smartphones have resolutions of 8-10Mpx) and being ready ...
0
votes
1answer
67 views
Detecting a single frequency in noisy data
I am not very experienced in signal processing, and it seems like this should be a simple problem. I have two computers, one plays a tone a 19 kHz at a sampling rate of 44.1 kHz, and the other listens ...
0
votes
1answer
64 views
How to apply Hamming Window?
I am new in matlab and signal processing. The time series that have been used are obtained from accelerometer in a building. As far as I understand both the time series' length and window function ...
-2
votes
2answers
37 views
DSP related websites and blog posts [duplicate]
Do you guys know good DSP related websited and blog posts?
I know that for example there is this site called Minutify:
http://www.minutify.com
which is blog posts regarding all areas of electrical ...
1
vote
1answer
59 views
Power or Energy Signal?
Can you tell me whether the following signal is a energy or power signal?
$$
x(n) = e^{j (n \pi/2 + \pi/8) }
$$
I've solved it and found it as it was neither power nor energy signal was that right?
1
vote
2answers
110 views
NAudio real-time equalizer
I have designed 9 IIR bandpass filters (chebyshev type 1, order 4) using fdatool in Matlab. Then I use a and b filter coefficients to apply it on differential equation. So, my question is how to apply ...
3
votes
1answer
65 views
What does the uncertainty principle say about recursive filters?
The uncertainty principle is usually stated as a relationship between a continuous signal and that signal's Fourier transform, and says that
$$
\int_{-\infty}^{\infty} \! x^2 f(x) \ \mathrm{dx} ...
3
votes
1answer
93 views
Implementation of basic 2-pole low-pass filter
I know this question has been asked to hell and back from many people, and that it will probably get downvoted until it's deleted, but please bear with me.
I am designing a sound engine for one of my ...
3
votes
2answers
85 views
Why integrate over $2\pi$ in inverse DTFT?
In DTFT of a signal, the spectrum of a sequence is periodic with period $2\pi$ and all the information needed for derivation of the original signal from its spectrum is contained in $\pi <\omega ...
3
votes
2answers
121 views
Why the power of periodic signal is square?
I have DSP in my academics and while going through the video lectures i am stuck regarding power of periodic signal.
Its mentioned as
$$P_{\text{avg}}= \frac{1}{N}\sum_{n=0}^{N-1}|x(n)|^2$$
my ...
3
votes
2answers
50 views
Multiple filters or not?
I'm processing audio signal sampled at 44.1 kHz. After some other processing, I need to filter the signal between ~5-50 Hz. Achieving this for a signal with such a high sampling frequency appears to ...
7
votes
1answer
134 views
'Best fit' motion curve for an unachievable profile
I have a discrete function that represents a 1d position in space over time. I have a motion system that would like to achieve this curve, but, due to constraints on jerk (3rd derivative) and ...
4
votes
3answers
219 views
Mathematically inclined Signal and Systems/Signal Processing book?
I'm an electronics engineering student with high inclination to analysis and pure mathematics. I was just wondering if there was any book ( or any resource ) that treats signal and systems and signal ...
2
votes
1answer
70 views
How to derive stability of analogue and digital systems
I'm trying to find out why digital systems are stable iff poles oh their transfer function are inside the unit circle (or are there any others conditions?).
I understand analogous systems are stable ...
3
votes
2answers
105 views
Main differences to take into account between continuous and discrete time signals
I started studying DSP and the first things that came out were the differences between continuous and discrete time signals. So, I was wondering if I understood well these concepts before I keep going ...
0
votes
1answer
45 views
Discretizing a continuous time signal
This may be a very straightforward question but I've been trying to understand this for a long time and can't wrap my head around it.
How would one go about discretizing the following continuous time ...
3
votes
1answer
68 views
Why is a feedback loop not represented by the least order transfer function?
I have a feedback loop with transfer $L(z)= \frac{H(z)C(z)}{1+H(Z)C(z)}$.
$H(z) = h$ and $C(z) = \frac{K}{z-\alpha}$.
If I manually calculate the transfer function, I get:
$L(z) = ...
2
votes
0answers
109 views
Simulink continuous to discrete question
I'm new to Matlab/Simulink and would like to convert the continuous system below to discrete for eventual conversion to C code. Matlab has a c2d function, but I don't know how to apply it to a ...
5
votes
3answers
129 views
Determining the mean of of a sampled signal (improvements to time averaging method)
I am sampling a signal at 1kHz, which is essentially a single-frequency sinusoid with a DC offset (and a small amount of noise). I don't know the precise frequency of the sinusoid (it is at most ...
5
votes
1answer
79 views
Cross Power Spectral Density of Unevenly Sampled Data
Here's my problem. The input signals $x$ and $y$ will be having the time value aligned with each other. However, the data are not evenly sampled. I would like to calculate CPSD of both signals.
The ...
2
votes
0answers
46 views
Kalman Filter: continuous state space, discrete observations
This is just an idea. How can we model the kalman filter to get the state representation in continuous space when the observations to the system are actually from the discrete space. The discrete ...
1
vote
2answers
80 views
one-source signal separation
I have a wav file which is gained by playing 2 different wav files with 2 speakers and recorded with mic. If I want to get one of the original signals using the resulting wav file and the other ...
3
votes
1answer
69 views
How to automatically detect blurred document images
The question I have is related to image quality evaluation. Suppose you are supposed to perform OCR (Optical Character Recognition) on a set of document images. Some images, however, are very ...
3
votes
1answer
87 views
How to compute dBFS?
I asked myself how to compute dBFS (dB full scale) from a value of sample between 1 and -1?
and in general?
0
votes
1answer
49 views
Format location from LPC magnitude
I am confusing when I find the lpc roots magnitude, f1=0.9313, f2=0.9308, f3=0.91 and f4=0.95 but when I look at LPC envelope the f1 is higher than f4 in term of magnitude in dB.
Could anybody explain ...
0
votes
1answer
46 views
doing sine regression to recover the paramters from a given signal
I have a discrete signal.
I want to do sinusidal regression to estimate the parameters
such as amplitude,phase, frequency etc
It is important to note I only have the signal values and
...
3
votes
2answers
65 views
What is the theoretic difference in the ways to compute the spectrogram?
I have noticed that the spectrogram for a audio signal is often calculated in different ways when the result from the DFT is transformed into real numbers; some tend to compute $|k|$ or $|k|^2$ while ...
0
votes
2answers
87 views
Calculate interbeat intervals
I'm currently reading a paper and I can't seem to make sense of a certain part. A link to the paper: removed
The part I don't quite get is on page 286 (after the part where they explain their ...
4
votes
0answers
74 views
Banding in the derivative of a lock-in amplifier signal
I'm analysing several measurements taken with a SR830 lockin amplifier.
These measurements look similar to this one.
Since I'm interrested in the derivative of the signal I took the numerical ...
0
votes
3answers
134 views
Finding the dominant tone in a signal
I am given 256 samples at a sampling rate of 48k and am asked to find the frequency of dominate tones and the amplitude of the largest tone. The data looks like this when plotted:
I assume I must ...
0
votes
1answer
81 views
How to calculate the energy levels of frequency intervals of an audio signal?
Using the Fourier transformation I can translate a signal from the time-domain to the frequency-domain. If I divide the frequency axis into intervals, how can I calculate the audios signals energy for ...
1
vote
1answer
95 views
Determine the type of filter from the transfer function
i got that system $x_n \to x_n-x_{n-1}$, so $h_n=[.....,0,1,-1,0,...]$, with $h_0=1$ and $h_1=-1$, so the transfer function given by:
$$\sum_{i=-\infty}^{\infty} h_ne^{-jwn} = ...
1
vote
0answers
39 views
Why is Cepstral Coefficients decorrelated?
Why is the Mel Frequency Cepstral Coefficient (MFCC) decorrelated in each frame; as far as I understand, this is because of the step where we take the Discrete cosine transform (DCT) of the log ...
2
votes
0answers
46 views
Are there any measurements or test for whether an audio signal is stationary?
I need to divide an audio signal into frames in which the signal can be assumed to be stationary. How can I measure whether an audio signal is stationary in a frame?
0
votes
0answers
64 views
How to measure the short-time change in an audio signal?
The choice of frame length for calculating the Mel Frequency Cepstral Coefficients of a signal, depend on the how much the signal change over a small time scale.
I guess that human speech change ...
2
votes
1answer
49 views
Finding Frequency Differences In Differing Amplitude Signals
I have two audio signals, both with supposedly matching frequencies at each time window. What I would like to do is to verify that the frequencies are identical. However, one was created at a higher ...
3
votes
1answer
59 views
Is this a valid z-transform of $ \frac{1}{n^2}u[n] $?
I was looking over some DSP and came across the following signal: $x[n] = 1/n$. So I wondered whether it had a z-transform but I soon realized that it fails to meet two conditions described here:
...
2
votes
0answers
36 views
How to model/estimate channel in discrete time with different sampling time?
I want to estimate a channel based on LTE 3GPP EVA with given power delay profile (set of average power and delay of channel taps).
...
2
votes
1answer
180 views
Amplitude and phase spectrum in MATLAB
I have a little problem with the subject Theory of signal. We were told to make amplitude and phase spectrum of cosinus in MATLAB, but we don't have results nor materials from our teachers, so we have ...
3
votes
1answer
117 views
Phase Locked Loop Basics
I am trying to better understand discrete-time PLLs. I drew a picture of a simple feedback system here:
I want to be able to describe and understand the system at v(t) and y(t). I found a fairly ...
0
votes
1answer
115 views
How to resample in MATLAB one signal that is supposed to be convolve with another one?
i have two audio signals .wav and i want to convolve them, the trouble is that the frequency do not fit, they aren´t just the same frecuency-lenght in the wavread arguments. i am supposed to use the ...
2
votes
1answer
88 views
response of algorithm in non-equidistant time
We are investigating ways to test a control algorithm. The algorithm has a non-equidistant track of input data (i.e. not every sample is valid, and we know it), and should output a series of ...
2
votes
2answers
64 views
Usage of Digital Cosine Transform in lossy compression of images
I was reading about Digital Cosine Transform (DCT Type-I) and it's use in JPEG.
I have the following doubt. My teacher offered an explanation which wasn't very convincing.
What property of Digital ...
