MACD could be based on Simple Moving Averages (SMA). There is no restrictions on what kind of moving averages (MA) or what combination of moving average has to be used in MACD calculations.
The MACD could be considered as one of the most used in technical analysis. It is based on Fast Moving Average (MA with lower bar period) and Slow MA (MA with larger bar period). To understand MACD you have to understand Moving Averages:
Technical analysis suggests that bullish trend is established when MACD moves above zero and bearish rend is established when MACD turns negative.
Therefore a simple trading system based on MACD would suggest: