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Questions tagged [frequency-analysis]

393 questions
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8 answers

How do I run a high pass or low pass filter on data points in R?

I am a beginner in R and I have tried to find information about the following without finding anything. The green graph in the picture is composed by the red and yellow graphs. But let's say that I only have the data points of something like the…
hlovdal
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Explaining The Count Sketch Algorithm

Can someone explain how the Count Sketch Algorithm works? I still can't figure out how hashes are used, for example. I have a hard time understanding this paper.
neilmarion
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How to calculate sound frequency in android?

I want to develop app to calculate Sound frequency in Android. Android Device will take Sound from microphone (i.e. out side sound) and I have one color background screen in app. on sound frequency changes i have to change background color of…
Ashish Wadatkar
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Determine "wiggliness" of set of data - Python

I'm working on a piece of software which needs to implement the wiggliness of a set of data. Here's a sample of the input I would receive, merged with the lightness plot of each vertical pixel strip: It is easy to see that the left margin is really…
Blender
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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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how can I statistic my key press frequency and count

I am try to remap my keyboard to type better. But I need to know the frequency of each key include symbol, It will be great if include tab shift ctrl. I need all the keypress acounting not only frequency of letters appears in english words. I am…
guilin 桂林
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Simple code to calculate frequency of Live Mic Audio using WebAudio API

I have website in which I need to display the frequency of the Live Mic Audio. I have a this code, but its extremely difficult to understand (It uses Fourier Transform and all). On some research I got to know of getByteFrequencyData() which returns…
FlyingAura
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Analyse frequency of mp3 files with python

I am trying to write a Python script to read an MP3 file and perform some analysis on the frequencies in it. In particular, I want a spectrogram (frequency vs time) as output. However, when I read the file using open() and piped the contents to a…
DrNightmare
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How do Mel Frequency Cepstrum Coefficients work?

I allready have FFT and pitch + absolute frequency calculated in real-time from input of microphone. Now I want to calculate the timbre. I saw Mel Frequency Cepstrum Coefficients - MFCCs but I didn't understand it very well. Can someone give me some…
André
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Cleaning up noisy Cepstrum results

I've been working on a simple frequency detection setup on the iphone. Analyzing in the frequency domain using FFT results has been somewhat unreliable in the presence of harmonics. I was hoping to use Cepstrum results to help decide what…
brodney
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Pyplot sorting y-values automatically

I have a frequency analysis of words said in episodes of my favorite show. I'm making a plot.barh(s1e1_y, s1e1_x) but it's sorting by words instead of values. The output of >>> s1e1_y is ['know', 'go', 'now', 'here', 'gonna', 'can', 'them', 'think',…
robert strickland
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FSK Demodulation - Parsing Japanese EWS Data

【This is not a duplicate. Similar questions are about scenarios where people have control over the source data. I do not.】 In Japan there's something called the "Emergency Warning Broadcasting System." It looks like this when activated:…
aaa
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Efficient algorithm to find most common phrases in a large volume of text

I am thinking about writing a program to collect for me the most common phrases in a large volume of the text. Had the problem been reduced to just finding words than that would be as simple as storing each new word in a hashmap and then increasing…
TheOne
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Improving frequency resolution of FFT output by limiting frequency range?

I am new to FFTs and signal processing, so hopefully this question makes sense and/or isn't stupid. I would like to perform spectrum analysis on a live audio signal. My goal is to find a good tradeoff between responsiveness and frequency resolution,…
gga80
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Lucene 4.4. How to get term frequency over all index?

I'm trying to compute tf-idf value of each term in a document. So, I iterate through the terms in a document and want to find the frequency of the term in the whole corpus and the number of documents in which the term appears. Following is my…
chepukha
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