[sdiy] Walsh update

[Scott Gravenhorst]

"John L Marshall" <john.l.marshall at gte.net> wrote:
>Magnus,
>
>It seems that you would want each note within an octave and each octave to
>have the same timbre. But, with the walsh generator you would want to freely
>manipulate the timbre, maybe through time. How are going to do that?
>Wouldn't it be cool to convert from Walsh to sine series and have sine
>octave draw bars?

This is a cool idea, it would be very conventionally intuitive 
performance-wise.  

Has anyone got any mp3 examples of what happens when one Walsh
coefficient is varied?  Would it be as useful to have Walsh
coefficient controls at the front panel as it would sine type
drawbars?

>The Walsh series would be longest for the lowest octave of notes but be very
>short for the highest octave unless your TOG is 32 or 64 times the highest
>note to be played.

PLLs on each of the TOG outputs could track and frequency multiply
the 12 pitches.  Lot's of parts though, at least two ICs per note.

>Take care,
>John
>
>----- Original Message -----
>From: Magnus Danielson <cfmd at swipnet.se>
>To: <madhun2001 at yahoo.com>
>Cc: <synth-diy at dropmix.xs4all.nl>
>Sent: Sunday, March 24, 2002 5:29 AM
>Subject: Re: [sdiy] Walsh update
>
>
>> From: Tim Ressel <madhun2001 at yahoo.com>
>> Subject: [sdiy] Walsh update
>> Date: Sat, 23 Mar 2002 15:44:01 -0800 (PST)
>>
>> > To all,
>> >
>> > AS you might have noticed, I kinda got distracted by
>> > this little midi project. No, I haven't forgotten
>> > about the Walsh thing. The board layout is done except
>> > for checking. I am planning on sending the board out
>> > for fab real soon now. The CPLD design has been done
>> > for a while, its time for me to do the next part.
>> >
>> > <------------------------------------------------>
>> > In the spirit of the list, does anyone want to
>> > volunteer to check the layout? I can mail a package
>> > with all the docs. Don't have my PDF writer yet, so it
>> > has to be snail-mail.
>> > <------------------------------------------------>
>> >
>> > This board will just be a breakout board for the Walsh
>> > CPLD. I have provided for both molex-style connectors
>> > (0.1") and dual-row header for ribbon cable. You can
>> > also populate the connector pins with machine SIP
>> > sockets to accept 24 ga solid wire.
>> >
>> > This little kit will consist of board, CPLD, and
>> > socket. Price will be in the $20-$25 range depending
>> > on how much the boards cost me. I'm not trying to get
>> > rich here, just trying to cover my costs.
>> >
>> > I will let you know when the stuff is available.
>>
>> Question:
>>
>> Why do you need a CPLD?
>> You can create any size of Walsh generator with a frequency divider
>> and a handfull of XNOR gates. For a organ setup, all you need is the
>> TOG part and 12 Walsh generators.
>>
>> Maybe I should do a simulation and hand it out.
>>
>> Cheers,
>> Magnus
>

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