# Questions tagged [r]

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### How to get rid of noise in audio files?

Is there any method to get rid of noise in wite circles of the spectrogram? I have done the high pass filter for a cut-off frequency of 1 kHz. And I'v also done a adptive noise reduction in adbobe ...
29 views

### How to get coordinates(x(time),y(frequency),z(intensity(db))) from spectrogram?

I have created this spectrogram from a wav file. Please have a look: enter image description here I want to get the x = time, y= frequency, z=intensity(db) of every pixel of the spectrogram. How can ...
93 views

### Butterworth filter's gain formula does not agree with R's signal package

I'm trying to calculate the Butterworth filter gain. If I use the formula mentioned on Wikipedia: $$G^2(\omega) = \frac{G_0^2} {1+\left(\frac{j\omega}{j\omega_c}\right)^{2n}}$$ I don't get a ...
78 views

### trying to reproduce the behavior of initial conditions for the filter delays of scipy lfilter with R

I'm trying to reproduce the behavior of lfilter and lfilter_zi (from scipy) in R (using signal package if possible). This is the example provided by ...
83 views

### Simulate butterworth filter with initial condition of state vector in R

I'm working in R with the packages signal and control (don't know wether these are even the best for my use case). I have a high ...
152 views

### Coefficient weights of Simple Moving Average (SMA) on SMA

A simple moving average (SMA: arithmetic mean) is a low-pass FIR-filter. When you cascade 2 SMA's with a window of length $n$, so when you apply the second SMA on the output of the first SMA, and you ...
18 views

### Structural time series model with multiplicative error term

I have a noisy time series measurement of a biological signal which I need to smoothen. I believe that the error of the measurement is proportional to the signal strength. I am currently working in R ...
37 views

### Time spans in coherence computation

Currently I'm writing my master thesis and I'm having troubles with coherence definition. My question is similar to https://stats.stackexchange.com/questions/92412/clear-steps-to-calculate-coherence-...
29 views

### Problem getting DTW to work for speech recognition

I used my ipad to record the words "This. Is. A. Test. This. Is. A. Test.", then downloaded it to my computer as a .MOV file and used ffmpeg to extract audio as WAV. I then used the tuneR package to ...
1k views

### Meaning of wavelet and scaling coefficients

What is the meaning of wavelet coefficients and scaling coefficients? E.g. for a sequence I obtained the following wavelet coeffients. How am I supposed to interpret them? I used ...
60 views

### FFT freqency bin center in R

I'm trying to do a spectral analysis in R. I learned it in Python from Allen Downey's ThinkDSP book. What is the R equivalent of the Python numpy function, numpy.fft.fftfreq? If you provide a window ...
500 views

### fft function in R vs spec function from 'seewave' package? They don't give a similar frequency spectra

I understand that spec will give me the frequency and the corresponding amplitude of that component, whereas fft will compute the DFT of the signal and throw the complex numbers for each component ...
83 views

### Unexpected frequency components found in Periodogram

I am trying to make sense of Digital Signal Processing with the help of R language. So, the issue came up when I tried to create a periodogram for a simple sine wave. The regular periodogram shows 2 ...
9 views

### impact of lombard effect on language identification

I have collected samples for 2 different languages. Now i need to extract MFCC features and identify which language using wave files. I need to do classification using R studio and perform an ...
391 views

### Estimate peak width from a vector that is a superposition of unknown number of identical Gaussian peaks with different heights?

If you have a vector that is a superposition of an unknown number of identical Gaussian shaped peaks/impulses of unknown width (but all the same width) and different amplitudes (with Poisson or ...
3k views

### How to make a Power Spectral Density Plot in R

I have a time series point process representing neuron spikes. I have computed and plotted autocovariance using acf but now I need to plot the Power Spectral ...
171 views

### Octave filtfilt converted to R code

R has a function called filtfilt that performs zero-phase digital filtering by processing the input data in both the forward and reverse directions. But it suffers from having steep transition bands....
167 views

### Pitch Calculation Error via Autocorrelation Method

Aim : Pitch Calculation Issue : The calculated pitch does not match the expected one. For instance, the output is approx. 'D3', however the expected output is 'C5'. Source Sound : https://...
136 views

### Reproducing paper results about a wavelet transformation using python [closed]

I have been reading this PhD theis about wavelets and I am trying to reproduce some of the results but I don't know the specific code to use to generate similar results. The original time series ...
2k views

### How to Calculate the Ambiguity Function

(Maybe this should be on Stackoverflow instead ...) What is the best way to calculate the ambiguity function? There are different implementations out there for Python (like PyTFTB or from ...
524 views

### Implementing FIR/IIR "alike" filter in R

I am new to signal processing. I am trying to simulate something similar to IIR/FIR filter with $k$ delays to imitate acoustic echo reflection. The difference equations for FIR and IIR respectively ...
511 views

### Finding baseline (reference) of nosiy data and lag/lead between 2 signals

I have 2 datasets which vary with time as shown in the figure - Sa – Red , Sb – BLACK . I am doing the analysis in R. The entire dataset and a segment of data from 30 - 31 s are shown below - - As ...
492 views

### Analysis of vibration signals

I have a vibration signal coming from a motor measured from accelerometer (Irregular Time series) and I need to use these signals for analysis purpose. I am in need to transform this signal to some ...
490 views

### Filter image in Fourier space imaginary components after ifft (R)

I want to high-pass filter an image in Fourier space. It works but the retransformed image has an imaginary part, what shouldn't be the case http://math.stackexchange.com/questions/867337/how-to-...
607 views

### Amplitude cutoff following FFT

suppose I have a noisy sine wave (as R code): ...
690 views

### Implementing a bandpass filter in R - this code's logic confuses me

I am reading this "how to" in R: http://www.inside-r.org/howto/time-series-analysis-and-order-prediction-r I am confused about the tutorial's implemented band pass filter. In particular, here's the ...