[sdiy] Question about "Musical Applications of Microprocessors" book

[Sam Ecoff]

Hi Gang,

So, at the kind advice of the list, I'm wading through "Musical  
Applications of Microprocessors". Very enlightening, and very  
enjoyable! I have a question, though. I was always taught that square  
waves were composed of only the odd harmonics. I believed that meant  
you *wouldn't* have a harmonic an octave higher than the fundamental,  
but on pages 23-25, it shows the process of creating a square wave by  
adding sine waves, one of which has a frequency which is double that  
of the fundamental. I have also noticed that while some books count  
the fundamental as the first harmonic, others treat an octave higher  
as the first harmonic. Regardless of which system, the info in the  
microprocessors book doesn't seem to work as they also show that you'd  
have to combine a sine wave whose frequency is three times the  
fundamental to get a square wave. What am I missing here?

Thanks!

Sam E.