A discrete signal or discrete-time signal is a time series consisting of a sequence of quantities.
3
votes
1answer
61 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
65 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
87 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
48 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 ...
1
vote
0answers
44 views
formant frequency bandwidth of LPC root
For formant estimation from LP polynomial roots, more roots amplitude shows that poles is near to unit circle in Z-domain but
Can anyone explain why the bandwidth of the formats must be small ?
I have ...
7
votes
1answer
123 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
176 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
63 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
88 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
41 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
62 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
61 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
123 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 ...
-1
votes
0answers
56 views
audio signal amplitude
Since we hear the same sound on the left and right channel that mean they should have the same value in the 2 channels but it is not the case with me. The values in both channels are the amplitude of ...
4
votes
1answer
63 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
40 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
42 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
61 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
72 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
45 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
45 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
60 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
84 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
71 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
114 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
72 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
59 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
32 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
42 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
62 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
47 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
55 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
29 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
135 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
108 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
68 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
82 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
62 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 ...
3
votes
0answers
65 views
Wavelet computation with filter bank - differing results
I'm trying to get a grip on Wavelets. I've read "Wavelets, Their Friends, and What They Can Do for You" which lead me to an implementation of the discrete DWT with filter banks. Basically, I'm using ...
3
votes
1answer
86 views
How do I find the Hilbert transform (qudrature) of a discrete signal by convolution with a Hilbert kernel?
Given a discrete real signal $ f_{re}(t) $ the (complex) analytic signal is given by:
$ x(t) = f_{re}(t) + j*f_{im}(t) $.
I want to calculate $f_{im}(t)$: the quadrature by convolving with a Hilbert ...
1
vote
2answers
206 views
Adding echo to audio sample
I have recorded my own voice in Matlab and I intend to add some echo to it.I came up with one solution for getting the desired echo effect:
Delay the sampled audio in the time domain and adding it ...
2
votes
2answers
113 views
How to predict the spectrum of an aliased/folded signal without looking at the FFT?
This seems like a trivial concept but I just can't get the hold of it. I have a signal with two complex sinusoids having frequencies -25MHz and 17MHz. Currently it is being sampled at 64MHz so I get ...
0
votes
2answers
135 views
How Discrete sequence could have more than one Frequency
I'm trying to understand Fast Fourier Transform in Detail to find out what exactly the frequencies when dealing with discrete sequence,
Here is what I've done,
First I've taken a Sinusoidal wave ...
3
votes
2answers
126 views
Using continuous verses discrete wavelet transform in digital applications
I am familiar with much of the mathematical background behind wavelets. However when implementing algorithms on a computer with wavelets I am less certain about whether I should be using continuous or ...
1
vote
0answers
71 views
Is $\delta(n) = u(n) - u(n-1)$?
In my text book, Digital Signal Processing, Principles, Algorithms, and Applications by John Proakis, it asks the question to show how $\delta(n) = u(n) - u(n-1)$.
I can understand how this is true ...
7
votes
1answer
199 views
Relationship between DCT and PCA
I have a basic implementation knowledge of the 2D 8x8 DCT used in image & video compression. Whilst reading about Principle Component Analysis, I can see a lot of similarity, albeit PCA is clearly ...
0
votes
1answer
47 views
Using phase information to extract sample values
I have one cycle of the following signal stored in a memory:
x(n)=sin(2 * pi * n/N + theta)
where theta= 2*pi*q/N and q, N are integers.
How do I use ...
2
votes
0answers
59 views
Voice sample prediction scheme
I have some telephone voice audio with occasional "blips" in the audio. The blips appear to come from an IP link buried in the PSTN (this is a conceptual explanation, so don't worry about things like ...
5
votes
5answers
233 views
What are some methods for detecting a sinusoid in noise?
I'm looking for a broad classification on the kinds of techniques available. Something I can use to begin a literature survey.
Some details:
should be feasible for real-time implementation.
Binary ...
3
votes
1answer
118 views
Is Kalman smoother symmetric in time?
Suppose my model is reversible in time (e.g. GPS + accelerometers for a vehicle), so that I can run Kalman filter forwards or backwards. Kalman filter, of course, cannot be symmetric, because it is ...
