# File rbSnack/tkSnackUtil.rb, line 85
  def getNextSeg(startPos=0,  minPower=nil, minDuration=nil) 
    minPower=@bkgrnd_power if minPower==nil
    minDuration= @min_duration if minDuration==nil
    endPos = @power.length-1
    x0, peak = nil, nil
    startPos.upto(endPos){ |x|
      y = @power[x]
      if y > minPower
        peak=y if peak==nil
        x0 = x if x0 == nil
        peak=[y,peak].max
      else
        return [x0,x] if x-x0 > minDuration and peak >@min_peak if x0!=nil
        x0=nil; 
        peak=nil;
      end      
    }
    return x0, nil
  end