Questions tagged [frequency]
Frequency in signal processing is the number of cycles (of the signal) per second.
509
questions
0
votes
3answers
70 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,...
0
votes
1answer
19 views
How to get RMS to Frequency chart for discrete samples of acceleration?
I’m 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 ...
-1
votes
0answers
20 views
I want to calculate the output of this system when the single pulse signal, δ (t), is applied to its input [closed]
how can I calculate the output of this system when the single pulse signal, δ (t), is applied to its input?
-1
votes
0answers
16 views
Pulse Repetition Frequency
Looking for the equation of how to calculate pulse repetition frequency. I’m looking to solve the maximum pulse repetition with a range of 300km.
1
vote
2answers
53 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. ...
2
votes
4answers
107 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 $$u(t)=e^{-j \alpha_1 \phi(...
0
votes
2answers
49 views
DFT frequency resolution exercise [closed]
I have a discrete signal that goes as follows:
$$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
votes
1answer
39 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 ...
0
votes
0answers
14 views
In an automotive ECU application for STM32, what ADC modes should I use? [migrated]
I am writing an application for the STM32f407-Discovery board that will use the ADCs present on it. I want to have access to all 17 of the input channels, and I will be using the HAL library to write ...
0
votes
0answers
30 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?
1
vote
0answers
18 views
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 ...
0
votes
0answers
8 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?
1
vote
1answer
59 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
votes
1answer
50 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 ...
-1
votes
1answer
48 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 ...
1
vote
2answers
63 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
votes
1answer
37 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 ...
0
votes
1answer
68 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$...
-3
votes
1answer
61 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
votes
0answers
29 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.
...
1
vote
1answer
27 views
How to calculate bitrate of PAL?
I have to calculate the bitrate of PAL format $\ (576*720) $. I have the following data:
$\ 25 $ frames per second
Interlaced
Interior representation is: $\ 4:2:0 $
$\ 8 $ bpp
I have tried the ...
0
votes
1answer
73 views
DC Components and Frequency
I have started learning digital communication and was on line coding. I read there are certain characteristics that we need to keep in mind while choosing the right line coding method. One of these is ...
1
vote
1answer
23 views
relationship of frequency with range in Underwater acoustic channel
I am interested to know what range of frequencies can be used/ or are effective for wireless communication, within the underwater acoustic channel. I do know a table exists from \cite{...
0
votes
0answers
240 views
How do I find the peak frequency of a wav file in python?
I am fairly new to python and signal processing and I was given a task to record audio for 'x' seconds and then find the peak frequency in the audio file.
So far I have successfully implemented the ...
0
votes
1answer
52 views
DFT and integer valued basis functions'sf requencies
In Matlab the function
W=dftmtx(N)
gives the DFT matrix of size N.
Each row is computed for an integer frequency k. $W_{k,n} = e^{-i2\pi kn/N}$, k-th frequency, ...
0
votes
1answer
73 views
Correlation between frequency and initial phase estimates using FFT
Why is there a high negative correlation between frequency estimation errors and initial phase estimation errors when measured using FFT?
I have a simple code showing this negative correlation.
is ...
0
votes
1answer
133 views
Power and Energy of an Audio file
I have a question about calculating the power and Energy of an audio recording.
I have imported a waveform of an audio recording in WAV format into Matlab and then calculated the energy and power in ...
1
vote
0answers
45 views
Aliased Signal's Frequency
So I have an incoming signal of 137.9 MHz and a sampling frequency of 1.4 MHz. Once sampled how do I calculate the aliased ...
1
vote
1answer
29 views
Digital carrier recovery
I was reading Chapter 2 from "Telecommunication Breakdown" by Johnson and Sethares and came across this paragraph:
However, sometimes it is more cost effective to perform certain tasks
in analog ...
0
votes
0answers
176 views
Butterworth cutoff frequency normalization
The issue: I am trying to reproduce the step detection technique as described in this paper. You can see the proposed step detection in the image below. The first part of this technique is to use a ...
2
votes
1answer
68 views
Is there a good method to extract a reference sin/cos from a group of signals?
For the removal of a pure interference from a group of sampled signals, if I know the exact frequency of the interference I can simply use an I/Q demodulation technique (i.e., a phasor projection) to ...
1
vote
1answer
57 views
STFT output frequency does not match sin wave frequency
I have the following function and pre definition for producing a sin and its' stft:
...
0
votes
0answers
79 views
How to find frequency and corresponding time for an audio signal?
I want to read in a sound file and get the frequency at each time interval of the signal.
I thought that the best way to approach this is by applying FFT to small chunks of the signal. Because FFT ...
1
vote
1answer
53 views
Calculate aliasing of $x_a(t) = \cos{(2\pi300t)} + \cos(2\pi600t)$ when sampled with $F_s = 1000$
I'm asked to sample the signal
$$x_a(t) = \cos{(2\pi300t)} + \cos(2\pi600t)$$
with sampling frequency $F_s = 1000$ and plot the magnitude spectrum for the resulting sampled signal.
My thinking is ...
-2
votes
1answer
114 views
What does a fractional frequency (for discrete-time signals) mean/how to interpret it? [closed]
This question has bugged me for a while as it's not addressed in any books I've read. I was wondering how folks from this community interpreted it. Below are my personal notes on the matter (please ...
2
votes
0answers
21 views
Is it possible to create a causal filter with a positively-sloped phase response?
I am currently prototyping a set of noise-cancelling headphones that utilize active EQ to modify the noise-cancelling signal, allowing the user to modify the frequencies that they hear or don't hear. ...
0
votes
0answers
55 views
Practical Signal Processing by Mark Owen Exercise 2.1. and 2.2
The following exercises don't have answers in Practical Signal Processing by Mark Owen. What is the author looking for here? A mathematical proof?
2.1 A cosine wave of frequency f is sampled at $t = ...
1
vote
0answers
14 views
Complex Spectral Phase Evolution (CSPE) Performance depending on signal windowing?
I am look into CSPE. "Signal Analysis Using the Complex Spectral Phase Evolution (CSPE) Method"
The method is simple. It compares the original signal's FFT and shifted signal FFT in phase domain so ...
2
votes
2answers
226 views
Do Fourier frequencies actually exist in real life in form of “fundamental frequency”?
For me, this is a very awkward question to be asked, as at this point in my studies I'm supposed to be quite expert with elementary mathematical tools like Fourier transforms, but this has always ...
0
votes
0answers
18 views
Interpreting results of multiplying signal and wavelets in the frequency domain
I have followed a lot of stuff on mike cohens website and have managed to make a filterbank of Morlet wavelets and convolve with an incoming block of samples. This of course is a computationally heave ...
1
vote
1answer
94 views
Term for integral multiples of fundamental period?
As we know that a signal has fundamental frequency and integral multiples of fundamental frequency are known as harmonics
I am curious about the term that will be used for integral multiples of ...
0
votes
1answer
104 views
Formant Analysis Frequency - What makes a peak value?
from spectrograms, how can you tell which peak is really a formant. Like why is the pink arrow the first formant. And in the spectrogram below, which has fewer samples, what makes a value the peak ...
1
vote
1answer
356 views
Chebyshev I or Chebyshev II?
I am new to DSP, and I am trying to recreate some analysis of a signal,
They use a chebyshev I filter to go from a 100Hz signal to a 50Hz signal. Whereas I am currently using a chebyshev II filter, ...
0
votes
0answers
48 views
histogram bin size vs. data sampling rate
I have a set of numerical signals that give me a set of zeros calculated based on some numerical procedure. I make a histogram of those zeros.
Here, a following problem arises:
If the histogram ...
0
votes
2answers
434 views
In case of using a Doppler radar, do we have to use IQ demodulation to find the direction of a target?
I want to know the way to find the velocity of a target by using a doppler radar.
I read some paper about it,
In summary,
send rf signal to a target
receive the reflected signal from the target.
...
0
votes
1answer
95 views
How do I find the frequency of a particular bin in a cosine transform, and two other questions
I have a discrete series of values and I have applied a Discrete Cosine Transform to it, obtaining values like:
...
0
votes
2answers
146 views
May I know how to find Time frequency power spectrogram of a signal?
I am analyzing EEG signal and I am unable to understand the term Time-Frequency Power Spectrogram. Please Can anyone help me?
Thank you in advance.
1
vote
1answer
106 views
How is frequency related to data rate?
How does (if it does) frequency affect/relates to Data Rate.
Why for example using the same modulation, LoRa (in the physical layer),
you get somewhere around 250kbps at 2.4Ghz and only 20kbps at ...
-1
votes
4answers
1k views
What are real-valued and complex signals and why is the Fourier transform of a real-valued signal Hermitian?
I have confusions in these concepts:
What are real-valued signals?
What is the difference between it and complex signals?
Why is it so that for real-valued signals, the spectrum of negative ...
0
votes
0answers
32 views
Temporally locating beats in an audio file
Imagine you have a long recording of a guitar player playing an arpeggio at a slow speed. To simplify, assume the tempo is 60 bpm or lower. I want to annotate this recording with the exact moments ...
