Questions tagged [frequency-domain]
The frequency-domain tag has no usage guidance.
247
questions
1
vote
1answer
45 views
Measuring frequency response with white noise signal
I need to measure a frequency response of an eleсtric circuit (simple like an RC-filter). I suppose that I can generate an input signal that has spectrum like white noise (for example, m-sequence ...
0
votes
1answer
23 views
How to do sliding window multiplication in frequency domain
I want to perform the following computations with the impulse response of length L of a LTI system:
Multiply the impulse response with a window w(n) of length M << L.
Take the FFT of the result ...
4
votes
4answers
169 views
Estimation of Amplitude, Frequency and Phase of Linear Combination of Harmonic Signal Beyond the Leakage Resolution of DFT
How can I find a rough ( as accurate as possible) Amplitude of each frequency when there is spectral leakage.
Currently, I am dealing with a system that contains special leakage which seems ...
0
votes
7answers
144 views
Where do harmonics come from?
At first, I thought harmonics come from the signal being periodic. However, we know a sine wave is also periodic but contains a single frequency and no harmonics.
A harmonic for me is a component (...
1
vote
1answer
47 views
Estimating the SNR of 2-FSK
I have some iq data recordings of a 2-FSK waveform that I've created periodograms from. How do you estimate the SNR of this waveform in the frequency domain? I've heard two opinions:
One:
Integrate ...
0
votes
1answer
28 views
Amplitude in frequency domain of the same signal measured at different bandwidth (f_max - f_min) and different FFT lines
Fourier series in complex form
Fourier series in trigonometry form
Here, I'm measuring the same signal (an impulse force - or at least as close as possible to an impulse, represented by a knocking ...
0
votes
0answers
18 views
What is the requirement to reconstruct a spatial domain signal if we sample in the frequency domain?
I've come across an interesting question with regarding to signal reconstruction.
The sampling theorem states that a signal in the time or spatial domain must be sampled at twice a rate twice the ...
0
votes
1answer
39 views
Meaning of the frequencies vector using fft
I'm so confused, and it would be nice if someone could clear my head, or at least direct me to suitable references.
Assume that I have two gaussian pulses with the same bandwidth in time, but for 2 ...
1
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0answers
19 views
The best method to convert piano sound to music notes in real time [duplicate]
I was looking for a way to convert piano sounds to piano notes for my research. I discovered the conversion of piano sound to piano notes using FFT and piano note recognition using CQT. I am also a ...
0
votes
1answer
36 views
I need help interpreting FFT diagram
I need help with analyzing the computed FFT of my signal. I don't wanna bother by going into the details of how my signal is formed so I will just state which frequencies I know my signal has. I know ...
3
votes
1answer
235 views
The Proper Way to Do Sinc Downsampling (DFT Downsampling) for Uniformly Sampled Discrete Signals with Finite Number of Samples
Given a signal $ \left\{ x [ 0 ], x [ 1 ], ..., x [ N - 1 ] \right\} $ what would be the correct way to downsample it in the frequency domain (Sinc interpolation)?
4
votes
1answer
69 views
Finding the Transfer Function of a Multiplicative Distortion in MATLAB
I have the frequency response of two signals shown above. One is uncontaminated, and the other is the same signal contaminated by a multiplicative distortion with two poles and two zeros. I need to ...
2
votes
1answer
64 views
Dealing with bias in an FFT for frequency correction
I'm working on using an FFT for frequency correction of a generic modulation signal. My algorithm basically attempts to balance the energy in the positive and negative frequencies of the FFT to be ...
0
votes
0answers
35 views
Extrapolation of band-limited frequency data
I'm now studying "How to do accurate transform from band-limited frequency data specifically S-parameter data of high speed interconnect to the causal impulse response in time domain. There are ...
0
votes
0answers
42 views
Average of magnitude data
I'm trying to reduce my magnitude spectra, which I need in octave bands. I have 5 measurements of a sound source, recorded with the same microphone at different times. I want to get an average model ...
2
votes
1answer
104 views
Designing a Chirp in the Frequency Domain
I am trying to create a chirp signal in the frequency domain, by simply setting the magnitudes of each frequency bin to one, and then setting the phase delay function such that the resulting time ...
1
vote
1answer
40 views
The cost function of LS algorithm
I'm trying to understand the derivation of LS algorithm for channel estimation in OFDM.
Could anyone explain why do we need complex conj transpose in the below equation?
1
vote
0answers
56 views
Sweep synthesis in frequency domain: How to correctly adjust magnitude?
I'm attempting to synthesize a logarithmic sweep signal to measure the IR of a system. For the most part, I'm following Section 5.2 of the paper Transfer Function Measurement with Sweeps.
To generate ...
0
votes
0answers
43 views
Is it possible to apply a fractional delay to even-length signals using the frequency-domain phase shift method?
Suppose I have the following Python function to apply any real-valued circular delay to a signal by multiplying by a phase factor in the frequency domain:
...
0
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0answers
25 views
In audio analysis, is the first rahmonic from the cepstrum equivalent to the first partial of a pitched sound?
I was reading this text from Oppenheim and Schafer, briefly explaining the concept of the cepstrum. I'm new to this concept.
He explains that the cepstrum is useful to quantize the distance between '...
0
votes
1answer
39 views
Continuously changing pitch of stable-pitch audio sample
I have an 44100-rate 4 second sample of a legato violin playing at 440 Hz. I would like to modulate this sample so that it starts at 440 Hz, then transforms its frequency continuously and ...
1
vote
3answers
292 views
If a square wave is a sum of odd harmonic impulses, why is it continuous in the frequency domain?
A square wave is a sum of sinusoids so surely it should be represented as individual discrete impulses in the frequency domain, where all other frequencies are 0. Why instead are those intermediate ...
1
vote
0answers
37 views
How to downsample a fourier transformed signal?
I have a signal of length 100000 timestamps sampled at a frequency of 25kHz. First I apply a high pass filtering at (300Hz) and then do the Fast Fourier Transformation. Then the absolute values are ...
0
votes
1answer
33 views
Names of system functions in frequency domain
I was just trying to refresh my systems theory known from long ago, and I realized that I had forgetten the name of the basic functions. Specifically, what are the names of these functions ...
-1
votes
1answer
59 views
Is pitch detection for bass instruments a solved theme?
I would like to know if pitch detection is a solved theme for an instrument like a bass (bass tones).
Is it, or there is always a percentage of error rate on the detection?
0
votes
1answer
64 views
Why use PSD to analyze a signal instead of its Fourier Transform?
Let's imagine I have a perfectly known signal $s(t)$ and I want to analyze its frequency components.
I noticed that mostly everyone would use the PSD of $s(t)$ to do that, instead of simply use the ...
1
vote
1answer
60 views
Steady state variance of a stochastic differential equation - relation between the frequency and time domains
Consider a stochastic differential equation:
$$
dx(t) = a x(t)dt + b y(t)dt \quad (1)
$$
where $y(t)$ is a stochastic process satisfying $\langle y(t)y(t')\rangle = \delta(t-t')$. We will assume that ...
0
votes
0answers
23 views
Does it make sense to apply convolution in the frequency dimension of a fourier transformed signal?
What I have is more likely a theoretical question. Since I am not from a signal processing background it is hard for me to grasp the issue in using convolution in the frequency dimension of a Fourier ...
-2
votes
1answer
23 views
Is it possible to prove that dither VS PWM can result the same output?
Assume that we have a SISO transfer function model $G(s)$ and we want to look how the output looks like when we have a input signal $u(t)$ that looks like this:
$$u_1(t) = \left\{\begin{matrix}
50 + ...
2
votes
2answers
161 views
Proof of fourier transformation of multiplication of two signals
I've been trying to find a proof of the following, but still I m unable to proof it, can someone help me?
$$
ℱ[x(t)g(t)] = \frac{1}{2\pi}
[X(\omega)*G(\omega)]
$$
-1
votes
1answer
51 views
Time domain analysis vs frequency domain analysis? Applications wise? [closed]
When do we use time domain analysis and when do we use frequency domain analysis?
As far i studied i know that when we need to study individual sinusoidal components of a signal, we choose frequency ...
0
votes
3answers
230 views
What is the Effect of Multiplying a Function by the Unit Impulse Function in the Frequency Domain?
I know about the the shifting property of the impulse function in the time domain as can be seen in equation $(1)$.
$$
\int_{-\infty}^{\infty} f(x)\delta(x - a)dx = f(a)\tag{1}
$$
But what is the ...
0
votes
1answer
90 views
phase offset extraction using matched filter
I'm looking for an application of detecting the drift of a received signal carrier frequency from ADC clock of the receiver (in case of no drift, ADC clock should be optimally an integer multiple of ...
0
votes
1answer
69 views
ouput of low pass filter
$$y[n]=(-1)^n w[n]+w[n]$$
$n$ ranges from $-\infty$ to $\infty$
where $w[n]$ is output of frequency response block with cutoff frequency = $\pi/2$, and input is unit impulse function.
I know ...
0
votes
1answer
77 views
Derivation of Circular Mean Square Error
I would like to understand how Eq. (36) in [2] was derived:
The rationale behind the definition of circular sample mean in Eq. (37) is clear, but there is no motiviation for the CMSE definition in Eq....
1
vote
2answers
50 views
Digital filtering based on frequency component amplitude… why not?
I've got a very general question.
I've just implemented a filter working in frequency domain that simply cuts every frequency component whose modulus amplitude falls below a certain threshold value. ...
1
vote
1answer
35 views
Continuous frequency grid to discrete grid
I am designing a controller for a system using several methods, one of which is a discrete method. In the continuous time I am looking at a logarithmically spaced frequency grid in the range $$\omega \...
1
vote
1answer
92 views
Why does this transfer function estimation not work? System identification
Goal:
I have an unknow dynmical system $G(s)$ and I want to find it from measurement data, output $y(t)$ and input $u(t)$. The data is frequency responses.
Method:
I begun first with creating the ...
4
votes
1answer
264 views
Convolution Theorem using DCT
I am trying to digest this paper.
[2002] Anna Usakova. Using Of Discrete Orthogonal Transforms For Convolution
So far, I've been successful with DFT and DHT.
Could someone give a hand with DCT?
I am ...
0
votes
1answer
76 views
Is it true that each and every signal has multiple frequency components?
Usually when we observe spectrum of a signal,we see multiple frequency components, each having different contribution to amplitude
But is it true that each and every signal has multiple frequency ...
1
vote
1answer
65 views
Harmonic Product Spectrum from FFT output to the fundamental frequency
I'm trying to do the HPS algorithm on my FFT output, but I'm stuck here.
My signal is from a bass (cable), 16bits, 48.000Hz.
I split in time domain the array of the whole record into multiple arrays ...
0
votes
2answers
101 views
How to avoid overtones in audio signal
I'm trying to make a program that catch and audio signal of a bass and show the notes that have been played. My program:
Gets the sound and put it in a double data type array. (48 000Hz, 16bits) ...
0
votes
2answers
143 views
Smoothing in frequency domain and impulse reponse of the filter in time-domain
I have a low-pass signal in frequency domain, $$\left[f_{min}=0, f_{max}=20\,\mathrm{GHz}\right]_{n=100}$$
After re-configuring the input signal as
$$X=\left[-f_{max},\ \dots\ -f_{min},\ \mathrm{DC},...
0
votes
1answer
30 views
Time and Frequency Domain Relationship
Why do we say that a good time response means a bad frequency response?
0
votes
1answer
1k views
How do I perform a time domain phase shift in the frequency domain?
I've seen some information on this topic around, but I don't quite understand it.
I have a time domain signal. I understand that if I want to time shift this signal, I can do so by multiplying its ...
0
votes
0answers
153 views
Frequency and Order maps
I'm new to python and I'm using it to analyse accelerations from an accelerometer ie. vibration analysis. For that I need to plot 2 types of diagrams:
1) Frequency map; frequency and time on the axis ...
0
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0answers
52 views
Time Frequency bin
I am doing research in audio signal processing for DOA estimation. I came across the term Time-Frequency bin. I have gone through several articles but none of them specify a TF bin rather it specifies ...
0
votes
1answer
143 views
Absolute value based AM envelope detection viewed in the frequency domain
In my understanding when a passband AM signal is demodulated with an envelope detector taking the absolute value restores the original baseband version of the signal and the low-pass filter removes ...
0
votes
1answer
57 views
GPS Receiver in Frequency Domain
I'm trying to transmit and receiver the GPS payload in both Time and Frequency Domain.
For transmitting and receiving in time domain :
...
0
votes
1answer
156 views
Spectrogram of an executable binary [closed]
One of the approaches I have been searching so far is the application of utilizing Neural Network to classify Spectrogram images, which is heavily used in speech recognition.
I am conducting an ...
