phasereset: Phase Reset

In connolr3/eegdatasim: Tool for EEG signals and ERPs

Phase Reset

Description

Generates EEG, assuming a Phase Reset Thoery Approach

Usage

phasereset (frames, epochs, srate, minfr, maxfr , position, tjitter)

Arguments

frames	number of signal frames per each trial
epochs	number of simulated trials
srate	sampling rate of simulated signal in Hz
minfr	minimum frequency of the sinusoid which is being reset
maxfr	maximum frequency of the sinusoid which is being reset
postion	position of the reset [in frames]; default: frames/2 => in the middle
tjitter	stdev of time jitter of the reset [in frames]; default: 0 => no jitter

Details

Function generates signal composed of a single sinusoid whose phase is being reset. The frequency of the sinusoid is chosen randomly from a specified range [minfr, maxfr]. The initial phase of the sinusoid is chosen randomly.

Value

signal

simulated EEG signal; vector: 1 by frames*epochs containing concatenated trials

Author(s)

Adapted from Yeung N,Bogacz R, Holroyd C, Nieuwenhuis S, Cohen J

References

https://data.mrc.ox.ac.uk/data-set/simulated-eeg-data-generator

Examples

#myphasereset<-phasereset (200, 10, 250, 3, 9 , 115, 0)
#plot(myphasereset[1:200],type="l")

## The function is currently defined as
phasereset <-
  function (frames,
            epochs,
            srate,
            minfr,
            maxfr,
            position = frames / 2,
            tjitter = 0) {
    signal <- replicate(epochs * frames, 0)#generating empty wave
    for (trial in 1:epochs) {
      wavefr = runif(1, 0, 1) * (maxfr - minfr) + minfr
      initphase = runif(1, 0, 1) * 2 * pi
      pos = position + round(runif(1, 0, 1) * tjitter)
      for (i in 1:frames) {
        if (i < pos) {
          phase = i / srate * 2 * pi * wavefr + initphase
        }
        else{
          phase = (i - pos) / srate * 2 * pi * wavefr
        }
        signal[(trial - 1) * frames + i] = sin(phase)
      }
    }
    return(signal)
  }

connolr3/eegdatasim documentation built on April 14, 2022, 10:39 a.m.