[sdiy] current question

[Tom Wiltshire]

On 26 Jul 2007, at 21:06, John Mahoney wrote:

> The goal is to produce a suboctave output that's not a square wave.

You can do this by mixing the output of a standard squarewave subosc  
with the ramp output from the main oscillator. When the peak-to-peak  
levels of the two signals are the same, the mixed result is a sub- 
octave ramp wave. I bet you've got all kinds of waveshaper circuits  
that'll let you do interesting things starting with a ramp wave!

hope this helps,
Tom

An aside:
Interestingly, you can see why this trick works if you think about  
the frequency spectrums of the two waves. The Sub-oct square (call it  
frequency f) includes f, 3f, 5f, 7f, 9f, etc. The ramp is twice the  
frequency, 2f, but includes all the harmonic multiples of 2f, eg 2f,  
4f, 6f, 8f, 10f. So you can see that it fills in the blanks!