Questions tagged [frequency]
Frequency in signal processing is the number of cycles (of the signal) per second.
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Why is the frequency measured in radians in filter design?
This is my first time posting a question, so sorry if my articulation is not proper.
I'v just started out with FIR filter design and I see the domain being -$\pi$ to $\pi$. Now I understand that ...
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1answer
24 views
RF Downconversion using Heterodyne Principle
after a RF down-conversion using heterodyning principle, will there be an information loss?
If we translate to a fixed IF frequency, is there is an intuitive way of explain that the information can be ...
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1answer
7 views
What is role of BW and frequency in internet speeds?
First the bandwidth (BW):
It is the amount of data that can be transferred simultaneously.just like more no. of highway lanes so that many cars can travel side by side simultaneously.
Frequency
It ...
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33 views
frequencies in frequency spectrum with no correlation together
I have a lack of understanding of the following questions:
If I have a signal from a motor that is recorded with an accelerometer. And the rotating speed of the motor is 150Hz(rpm 9000 ), I can see in ...
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11 views
How to measure SNR of an image with banding noise (high and low spatial frequency noise)?
I have a thermal image of an object, for example, a lamp. Initially, the lamp is off at ambient temperature. The resulting thermal image should look highly uniform (a), but it contains expected ...
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2answers
22 views
What does following statement mean: “ Simulation was done at the rate of 12 samples per cycle of 50Hz a.c.”
I am very new to the signal processing world and i am currently doing a project of studying frequency components in electrical machines. I am simulating the system in PSCAD. But i need to simulate the ...
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1answer
50 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 ...
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23 views
Signal is not audible after frequency re-sampling
I'm trying to change the frequency of an audio signal from 22050hz to 500hz. I'm using librosa to read the wav audio and pass the custom sampling rate as 500. Once read, I'm saving it back to audio ...
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2answers
45 views
Increasing parameter $\omega$ in $x[n] = e^{j\omega n }$
Suppose $x[n] = e^{j\omega n }$. I've seen following statement many times in the different sources:
For the discrete-time sinusoidal signal $x[n]$, as $\omega$ increases from $\omega = 0$ toward $\...
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3answers
405 views
How do I find a 50Hz sin/cos signal in a measurement among other frequencies and noise?
I measure magnetic fields with high precision, in a gradiometer setup with fluxgate magnetometers, sampling at 2000Hz. I can have big data sets if I want to - one is 600000+ samples long. I need to ...
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1answer
23 views
Possibilities to get the amplitude of a signal at specific frequency from IQ
I'm newbie to the dsp topic and my understanding of math symbols is limited.
So at the moment I'm little bit lost to find the right resources.
I receive an IQ stream from a SDR.
Sample rate: 250k/s
...
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52 views
Is it better to use sampling rates which are a power of 2? 32-64-128-256-512Hz? instead of using for example 30- 60-100-250-500Hz?
I am recently working with a sensor that I its sampling frequency can only be configured to either 32hz- 64hz- 128hz-256hz... and I was wondering whether using such sampling frequencies have any ...
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1answer
16 views
Difference in frequency spectrum of continuous time signal and discrete time signal?
I am studying chapter 4 of book signal processing first
There i came across a concept which says that(what i have understood)the spectrum of continuous time signal has limited number of lines while ...
2
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1answer
48 views
Detection Bandwidth for Noise Power Calculation
I am trying to calculate the $P_{noise}$ in an experimental setup, such as given
below. The DUT is excited at a predefined frequency, $f$ , with
power $P_\text{in}$. The total power is measured by the ...
1
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1answer
68 views
PLL for Phase Demodulation and Carrier Tracking
I've been playing around with using a PLL for phase demodulation and it's working pretty well. The PLL locks to the carrier and the error term is the demodulated message signal. However, depending on ...
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144 views
Does negative frequency actually exist or it is just theoretical?
This below questions gives good explanation regarding negative frequency
What is the physical significance of negative frequencies?
But I have one query
Does negative frequency only exist ...
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1answer
42 views
Representing a sinusoidal signal in terms of positive and negative frequency components?
I am reading "signal processing first " by Mcclean
https://www.amazon.com/Signal-Processing-First-James-McClellan/dp/0130909998
In article 2.5.4, author discusses about representation of real ...
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4answers
52 views
Angular frequency ($\omega$) vs regular frequency($f$)?
What is difference between angular frequency ($\omega$) and regular frequency($f$)?
As far as i am able to understand is that electric power signal has $f=60Hz$ and many other cases where i see "$f$" ...
2
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3answers
86 views
What is difference between frequency and pitch?in nutshell and simple words?
Although both are some how directly related
Such that when one increases,the other one also increases
I have read different Google results but couldn't understand .
I want to know what is exact ...
0
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1answer
72 views
How can I improve the resolution of a spectrogram of a low-frequency signal with high sampling frequency (Python)?
Imagine you have signals $x_1(t)$ and $x_2(t)$ that contain a limited number of periods of low frequency oscillations and are sampled at 44100Hz (coming from an external source) and you want to obtain ...
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1answer
29 views
Time and Frequency Domain Relationship
Why do we say that a good time response means a bad frequency response?
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2answers
34 views
Carrier Frequency Offset Correction Limitations
I know that carrier frequency offset is typically detected and corrected in OFDM systems. I was wondering if there is a way to determine the theoretical limit to how much offset can be successfully "...
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47 views
Frequency Smoothing for Noise Reduction
I'm trying to understand the Noise Reduction implementation in Audacity and I was wondering how the Frequency Smoothing is implemented.
Frequency Smoothing (bands): At values of 1 or higher, this ...
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2answers
72 views
Why is the digital frequency highest at $\pi$ and what does it mean in terms of analog frequency? [duplicate]
I can't seem to comprehend why the digital frequency is highest at $\pi$. I know the relationship between the digital and analog frequency is given by:
$$\omega = 2\pi\frac{F}{F_s}=2\pi f$$
Where $F$ ...
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2answers
42 views
Extracting different frequency bands (alpha, beta, gamma) from brain activity data
I am new to signal processing and despite googling about my question, I still couldn't find the solution.
I have an Electrocorticography (ECoG) dataset. This consists of recording brain activity from ...
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2answers
27 views
Discrete-time system: getting the true frequency from normalized frequency
LŠµt's say that i have a plot where i can see the spectrum of some discrete signal and let's say that it's x axis is normalized (by normalized i mean $\omega/\pi$ on the $x$ axis). Now, i know that in ...
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51 views
How to extract information about each constituent 'wave' of a signal?
I have a vector containing wind speeds sampled at 1Hz over ten minutes.
I have applied a lowpass filter of 0.25Hz to get only the wind speeds I am interested in.
I now want to use MATLAB to ...
0
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1answer
33 views
Time response of complex frequency response function
In the frequency domain I have the following function:
$$
H(f)=A(f)\cdot e^{i\beta(f)}
$$
Where both $A(f)$ and $\beta(f)$ are known functions. The thing I would like to do is to model the response ...
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5answers
1k views
A question about sampling rate of cosine signal
Given $$c(t) = \cos(2\pi\cdot 30 \cdot t) $$
If we sample this signal at the Nyquist rate 60 Hz and at a higher rate of 80 Hz, we get the following:
There is no aliasing as $f$ = 30 Hz is less than ...
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0answers
44 views
frequency amplitude asymmetry
I want to calculate the frequency amplitude asymmetry between two signals, EEG signals in particular. As a result, I expect a value ranging from 0 to 1. I have some references regarding that, but it's ...
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1answer
192 views
The selection of the amplitude of the signal, consisting of rectangular pulses, at different frequencies
I already asked a similar question, but did not receive an answer and did not find a solution, I want to make another attempt to get to the bottom of the truth.
There is a signal consisting of ...
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2answers
56 views
Sampling $x(t)=\cos(4\pi t)+\cos(2\pi t)$
Imagine that we sample the signal $x(t)=\cos(4\pi t)+\cos(2\pi t)$ with a certain sample frequency $f_s$ and we obtain $x[n]$. Now, by ideal interpolation, we get $y(t)$ from $x[n]$.
How can we know ...
3
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1answer
78 views
Positive slope of BER with a greater frequency deviation?
I am trying to implement a frequency-modulated communication channel on MatLab. However, there is something I don't understand about the sensitivity of the frequency modulator (or the frequency ...
0
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3answers
130 views
Does a .wav file created from a .mp3 file have better quality than the .mp3 file itself?
A .wav file created from a .mp3 file has the same frequency domain plot as the mp3 file itself https://stackoverflow.com/questions/58706674/difference-between-frequency-domain-in-mp3-and-wav.
However,...
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1answer
59 views
How to get RMS to Frequency chart for discrete samples of acceleration?
Iām reading a book on Motorcycle dynamics and want to compare the vibration profile of my motorbike against this chart:
I am not sure how to get the RMS of acceleration at different frequencies.
I ...
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2answers
60 views
Estimate “speed” of repeating signal pattern
I have a digitized signal containing a repeating pattern. One could call it periodic, but the time for one period is not constant. The "speed" with which the period is advanced can change over time. ...
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4answers
124 views
instantaneous frequency for a sum
In the literature, the instantaneous frequency for a signal $s(t)=e^{-j \phi(t)}$ is given by: $$f(t)=\tfrac{1}{2\pi}\frac{d\phi(t)}{dt}$$
This my problem: I have a signal $$u(t)=e^{-j \alpha_1 \phi(...
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2answers
65 views
DFT frequency resolution exercise [closed]
I have a discrete signal that goes as follows:
$$x[n]=[-1,4,-1,0]$$
I have already done the DFT for the signal, with the following result:
$$X[0] = 2, X[1]=-4i,X[2]=-6,X[3]=4i$$
But for some reason, I ...
0
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1answer
58 views
Modal analysis and frequency response function - interpretation needed
For couple of weeks now, I have been trying to measure cutting forces during machining processes. The system which I am currently examining is highly distorted at high frequencies due to its ...
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0answers
35 views
FFT first frequency
I have some problems understanding FFT. If I know Fourier analysis frame (1024 samples) and sample rate (48 000 Hz), how can I find the first frequency of harmonic sines and cosines?
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Measuring respiratory rate from a 3d accelerometer signal? How do I preprocess this data and move forward with it?
I have read a decent amount of papers that used wrist smartwatches to measure respiratory rate, or papers that used sensors attached to a persons chest. I can link them if it is necessary.
I am ...
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0answers
9 views
Physical meaning of a signal with 4 IMF?
If a signal is composed of four implicit mode functions, where the last one is a constant residue, does the instantaneous frequecy of the signal have physical meaning?
2
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1answer
211 views
Scaling Function in Wavelet Analysis
I was watching a YouTube tutorial on wavelets https://www.youtube.com/watch?v=wgRgodvU_Ms, where the presenter showed that if we multiply a Gaussian with a sine wave (and follow some other conditions),...
0
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1answer
96 views
with given Sampling rate, what max frequency human voice can be captured?
I'm new to signal processing and sampling rate, I was asked interview question related to this.
This is the exact question asked:
With 8Khz of sampling rate, whats the max frequency that human ...
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1answer
60 views
Sampling of frequency response
Let's consider any physical quantity depending on the frequency. For example, the impedance of a certain electrical component: $Z(f)$.
Now, imagine to measure it in a continuous interval of ...
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2answers
127 views
What Is the Bilateral Filter Category: LPF, HPF, BPF or BSF?
I`m reading about Bilateral filter with images, I knew that it uses Gaussian filter (which is a LPF) as a domain filter plus a range filter and it is used to preserve edges(high freq component).
Can ...
0
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1answer
48 views
How does one interpret an element of the “transfer matrix” used to calculate frequency domain granger causality (via VAR models)?
I am attempting to gain a better mathematical understanding for how autoregressive models can be used to infer frequency-domain granger causality. All freq. domain measures of causality that utilize ...
2
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2answers
117 views
Tracking a sine wave with noise
This will probably be an extremely simple question for some one with any background in signal processing(not my background)
Let say I have signal $$x(t)=A\sin(\omega t)$$ where A is known and $\omega$...
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1answer
93 views
White noise in range of frequencies [duplicate]
If I have this function:
while (true)
{
frequency = 8000;
wave = sin(sampleNumber*2*PI*frequency/sampleRate)
sampleNumber++;
}
it will produce an ...
0
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2answers
111 views
Difference between OFDM and FDM
In Frequency Division Multiplexing we provide one channel to one user.
Example like BandWidth of user1's voice is 200Khz. I provide one channel of 200KHz in FDM for uplink as shown in the figure.
...
