[sdiy] harmonic generator

[John L Marshall]

<snip>
> What's a Walsh function??

Walsh functions are to rectangular waves as Fourier is to sine waves. The
main feature for electronic music is that a binary divider chain with
exclusive-or gates will generte the walsh values. The walsh values may be
combined in proportion to produce a series of sine waves or any other shape
wave. Do a google search and you will find many academic sites that discuss
Walsh functions. There are a few of us S-DIY that have built circuits.
Bernie Hutchins, Electronotes had a series of articles on Walsh functions.
Cellular telephone CDMA technology uses Walsh codes for encoding and
decoding voice and control channels.
>
> >3. Divider chains
> >4. Look up tables
> >5. Rate multipliers
>
> How does a rate multiplier work??
>
Rate multipliers one of the coolest logic circuits around. Look at 7497 or
74167. I think these were only made by Texas Instruments. There are a couple
of CMOS rate multipliers as well. Think of a logic block with a clock input,
a binary select the rate out and output at the rate. For 74167; 1 clock in
10, 2 clocks in 10, 3 clocks in 10. The down side? The clock rate output is
not evenly spaced. It must be divided down to reduce pulse "jitter".