Published article "A Universal Channel with the Graphical Interface".
All channel indicators are displayed as three lines, including central, top and bottom lines. The drawing principle of the central line is similar to a moving average, while the moving average indicator is mostly used for drawing channels. The top and bottom lines are located at equal distances from the central line. This distance can be determined in points, as percent of price (the Envelopes indicator), using a standard deviation value (Bollinger Bands), or an ATR value (Keltner channel).