Thanks JeffBart for the extracts from the manual they are an amazing resource..have you got the 2500 one too? I have that manual and the 1601 one too, i thought it would help me better understand our synth as the manual we got is not that helpful at times.
The exercises are very thorough and at times if you get distracted read like science papers. I don't have a problem with that as i studied the physics of sound and electronics at university, when we apply it to sound from a a synth it can explain a lot of things. As you say you understand about 60%, which is about what i understand you're not alone there it is a bit baffling eh?
From researching the way distortion effects for guitar pedals the harmonic content of an asymmetrical wave is very interesting and shifts more towards odd harmonic distortion where the asymmetrical as a mix but less volume. See http://www.thegearpage.net/board/index.php?threads/symmetrical-vs-asymmetrical-clipping.520950/
If the ring modulator has a DC component , like DC offset we know and loathe it skew one half of the waveform into clipping leaving the other clean. So if we allow a DC offset we change the harmonics produced. So having a DC component / switch would be desirable and allow us to produce some strange wave shape and unusual harmonics.