xjo weekend zoomba lounge, page-98

Jako or GJ OR Red or anyone, I have been hand building a few MACD calcs in excel (why? because it forces me to look closely at the data and the results). However, when I get to the signal line calculation I am a little stumped as some take a SMA and others say take an EMA of the MACD line. Any input?

Also, if an EMA what is the formula to calculate the signal line? (""using Close - EMA(previous day)} x multiplier + EMA(previous day"" doesn't work as what "close" would you use??? - you end up with zero on the numerator)