private void UpdateData()
        {
            lock (this)
            {
                for (int i = 0; i < Count; i++)
                {
                    _re[i] = 2.0 * Math.Sin(2 * Math.PI * i / 20) +
                             5.0 * Math.Sin(2 * Math.PI * i / 10) +
                             2.0 * _random.NextDouble();
                    _im[i] = IsFrequencyDomain ? 0.0 : i;
                }

                if (IsFrequencyDomain)
                {
                    _transform.run(_re, _im);
                    for (int i = 0; i < Count; i++)
                    {
                        double mag = Math.Sqrt(_re[i] * _re[i] + _im[i] * _im[i]);
                        _re[i] = 20 * Math.Log10(mag / Count);
                        _im[i] = i;
                    }
                }

                DataSeries.SeriesName = YAxisTitle;
                DataSeries.Clear();
                DataSeries.Append(_im, _re);
            }
        }