Questions tagged [frequency-analysis]
361 questions
6
votes
2 answers
Am I using the Fourier transformation the right way?
I am wondering if I am using Fourier Transformation in MATLAB the right way. I want to have all the average amplitudes for frequencies in a song. For testing purposes I am using a free mp3 download of Beethovens "For Elise" which I converted to a 8…
stefan.at.wpf
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5
votes
3 answers
How to extract a specific frequency range from a .wav file?
I'm really new on sound processing, so maybe my question will be trivial.
What I want to do is to extract a specific frequency range (let's say 150-400 Hz) from a wav file, using R. In other words, I want to create another wave file (wave2) that…
Tommaso
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5
votes
3 answers
How to use cepstral?
Recently I asked this question: How to get the fundamental frequency from FFT? (you don't actually need to read it)
My doubt right now it: how to use the cepstral algorithm?
I just don't know how to use it because the only language that I know is…
Lucas Speranza
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5
votes
13 answers
Counting Letter Frequency in a String (Python)
I am trying to count the occurrences of each letter of a word
word = input("Enter a word")
Alphabet=['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z']
for i in range(0,26):
…
Kelvin San
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5
votes
1 answer
Frequency shift using FFT in Matlab
I am working on implementing BFSK modulation and demodulation with frequency hopping and I need to test my results using Matlab. The output the I am getting from my BFSK program is an array of sine values corresponding to the carrier signal for…
anshu
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4
votes
2 answers
SQL - Determine the most frequently occuring words within a column
Is there an easy way of determining the most frequently occuring word in a column/field using T-SQL or VBA?
I am working on a fuzzy matching system for two given recordsets and would like to produce a matching string where the most frequently…
user1075081
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4
votes
5 answers
Calculate Character Frequency in Message using Perl
I am writing a Perl Script to find out the frequency of occurrence of characters in a message. Here is the logic I am following:
Read one char at a time from the message using getc() and store it into an array.
Run a for loop starting from index 0…
Neon Flash
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4
votes
1 answer
Auriotouch, get musical note from frequency FFT
I'm developing a kind of guitar tuner.
I have a function that gives me the FFT, and the values of the FFt for each frequency.
How do I get the musical note from there? Do I have to chose the highest peak?
for(y=0; y
Neva
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4
votes
1 answer
AudioKit 4.2.3 Crash Microphone Frequency Analysis Swift 4.1
I just updated to the latest AudioKit version 4.2.3 and Swift 4.1 I'm getting a crash at audiokit.start() that I can't decipher. Please lmk if you need more of the error code.
AURemoteIO::IOThread (21): EXC_BAD_ACCESS (code=1,…
robinyapockets
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4
votes
3 answers
Summary in R for frequency tables?
I have a set of user recommandations
review=matrix(c(5:1,10,2,1,1,2), nrow=5, ncol=2, dimnames=list(NULL,c("Star","Votes")))
and wanted to use summary(review) to show basic properties mean, median, quartiles and min max.
But it gives back the…
Roland Kofler
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4
votes
1 answer
Oscillation and frequency spectrum through a Fourier transform
I'm trying to find the oscillation and spectrum frequency of the waveform generated by a vector of data representing the motion of a pixel in an image.
The data is stored in a .txt file, as follows:
75.000000
60.000000
52.000000
61.000000…
Jorge Cruz
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4
votes
3 answers
Cryptography. English "normal text"?
I was asked to make a software that will encrypt and decrypt a "normal English" text based on letter frequencies.
The question is where do I find some text samples where the official frequencies will match?
So far, I have tried "War and Peace" by…
sdadffdfd
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4
votes
2 answers
How to extract the peak at a specific frequency in python
I want to know how much energy is at a specific frequency in a signal. I am using FFT to get the spectrum, and the frequency step is determined by the length of my signal.
My spectrum looks, for example, like this :
I want to get the spectrum peak…
FunkySheep
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4
votes
2 answers
SQL for two-way frequency table using a string valued variable
Consider the following event data in PostgreSQL 9.4:
eventTime | eventName
2015-09-25 18:00:00 | 'AAA'
2015-09-25 17:00:00 | 'BBB'
2015-09-25 16:00:00 | 'BBB'
2015-09-25 15:00:00 | 'BBB'
2015-09-25 14:00:00 | 'AAA'
2015-09-26 13:00:00 |…
JohnH
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4
votes
4 answers
Word Frequency in text using Python but disregard stop words
This gives me a frequency of words in a text:
fullWords = re.findall(r'\w+', allText)
d = defaultdict(int)
for word in fullWords :
d[word] += 1
finalFreq = sorted(d.iteritems(), key = operator.itemgetter(1), reverse=True)
…
demos
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