scripts/channelClasses/mock_ec/Sine.java

/////////////////////////////////////////////////////////////////
// This script generates pure sine waves, with different freqs at each site.
//
// Run with (for example)
//    java -cp build:lib/derby.jar -Dserver.cache.enable=false -Djava.library.path=c frontendClasses/CLI -scriptChannel mock_ec/Sine -reviewSeries -paradigm ec -binZ site -transform power -display "TiledStack()" "Export(to=window, as=txt)" -v
/////////////////////////////////////////////////////////////////
package mock_ec;

import java.io.*;
import java.util.*;
import java.text.NumberFormat;

import epochClasses.*;
import generalClasses.*;
import recordingClasses.Recording;
import seriesClasses.*;
import seriesClasses.seriesGeneration.Erlang;
import channelClasses.ChannelScript;
import static channelClasses.Channel.*;

/////////////////////////////////////////////////////////////////
/** This script generates pure sine waves, with different freqs at each site.
 *
 * <p>The intended effect is:
 * <ul><li>To check relation between amplitude and power: power should be 
 *         0.5*amplitude^2, irrespective of window size and overlap</li>
 *     <li>Demonstrate spectral leakage</li>
 * </ul>
 */
public class Sine extends ChannelScript
{
    /** Recording instance to be operated on */
    Recording rec = null;
    /** Time series */
    ArrayList<SeriesAnalog> list = new ArrayList<SeriesAnalog>();
    /** Events.  May be left empty */
    ArrayList<Event> ev = new ArrayList<Event>();

    ////////////////////////////////////////////////////////////////////
    /** Initialize instance by setting its parameters to default values.
     */
    public Sine(Recording rec) {
        this.rec = rec;
    } // Sine

    ////////////////////////////////////////////////////////////////////
    /** Update recording data by performing channel-oriented operations.
     */
    public void update() {
        // Template - used to encapsulate all sampling characteristics
        float x0 = 0.0f;             // in seconds: times start at x0
        float xDelta = 0.004f;       // in seconds: times increment by xDelta
        float duration = 120.0f;     // in seconds: times end at x0+duration
        int nIndexes = Math.round(duration/xDelta);
        SeriesAnalog template = new SeriesAnalog(new SiteSet(), // sites
                                                 x0,            // x0
                                                 xDelta,        // xDelta
                                                 new Units(Unit.s),  // xUnits
                                                 nIndexes,      // # samples
                                                 new Units(Unit.uV), // yUnits
                                                 DataMode.EEG); // DataMode

        // Channels  containing frequencies in the range [f0,f1] Hz
        int nChans = 20;
        double f0 = 1.1;
        double f1 = 80.0;
        double step = Math.log(f1/f0)/(nChans-1);
        String[] labels = new String[nChans];
        NumberFormat formatter = NumberFormat.getNumberInstance();
        formatter.setMaximumFractionDigits(1);
        for(int i=0; i<nChans; i++) {
            double f = Math.exp(Math.log(f0)+i*step);
            labels[i] = formatter.format(f);
        }
        // Epochs will later be defined as 2.0 secs long, i.e. spectral 
        // res = 0.5 Hz.  Accordingly, let's ensure that at least one 
        // channel contains an integer multiple of this
        labels[3] = "2.0";

        for(int site=0; site<labels.length; site++) {
            // What modality?
            DataMode mode = DataMode.EEG;

            // Parameters of sine wave
            float amplitude = (float)Math.sqrt(2.0);
            float freq = Float.parseFloat(labels[site]);
            float twoPiF = (float)(2*Math.PI*freq);

            // Create time series, with general character matching template
            SeriesAnalog series = template.clone().setRamp(0.0f,twoPiF);
            series.transformSin().mul(amplitude);
            series.setSites(new SiteSet(new Site(labels[site])));

            // Append series to result
            list.add(series);
        }

        // Add synthetic time series to the currently empty Recording
        replaceAllSeries(rec, list);
        replaceAllEvents(rec, ev);
    } // update

    ////////////////////////////////////////////////////////////////////
    /** Dump summary of this class or object
     * @return String representation of this object
     */
    public String toString() {
        String s = "<<<"+this.getClass().toString()+">>>\n";
        return s;
    } // toString

}