Subject: BBD delays etc. (was Re: convolvotrons)

From: Chris Hand <[email-masked]>
Date: 22 Mar 92 17:27

RFC-822-HEADERS:
X-Mailer: ELM [version 2.3 PL11]

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> 
> I believe that's a National Semiconductor part?  The external components
> are good news though.. you can trim the bandwidth (sounds like the
> usual "feedback-filter" type of circuit).  
> 
> The design will have to go like this: an external delay circuit (do
> you know of any better parts than the SAD1024?  That's what I used 
> in my last model) to set the "azimulth" delay, then the equalizer
> set for 7 bands between 1.5 and 18 KHz.  Some sort of interface 
> to the PC, too.   May be tough finding someone who carries the chip
> though (local suppliers want you to order 30-100 minimum...
> 
> -Dave Stampe
> 
Could be Nat Semi, but they're usually "LM"; don't know about "LMC".
(IC databooks, anyone?).

As far as suppliers go, it *used* to be available mail-order from
Maplin Electronic supplies here in the UK, but it's gone from this
year's catalogue. :-(  Maplin cater for hobbyists, so if it's available
then quantity is not a problem.  They take credit card orders by
modem too.

They've got some new bucket-brigade delay chips though:
I don't have specs for the SAD1024, so I don't know if they're
better.

MN3207 1024-stage low voltage BBD.  Max audio delay 51.2ms
MN3011 3328-stage BBD w/ 6 taps.  Max audio delay 166.4ms.
	"6 o/p's are provided with different non-related delay
	times so that a natural reverb effect can be created
	by mixing these signals."

They also have a "speech pitch shifter IC" (MSM6322) that
will shift the pitch of an audio signal (8kHz B/W I think)
up or down 1 octave.  How useful would this be for simulating
doppler in moving sound sources?

Chris

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From: Dave Stampe-Psy+Eng <dstamp@watserv1>
Date: Sun, 22 Mar 92 23:44:38 -0500

I suppose the MN3207 can be split into 2 shorter lines (the SAD1024
could)?  The MN3011 sounds right for the reverb: only 1 is needed for
the whole unit.  Dunno about theshifter though: it's probably fixed
to 1/2 or 2x.  Easier to "warp" the sound source, I guess.

Any idea who makes the "MN" parts?  Sharp, perhaps?

- Dave Stampe

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From: [email-masked] (Thomas Clarke)
Date: Mon, 23 Mar 92 08:05:30 EST

MN parts are by Panasonic now, used to be an American company (of  
course :-)

DigiKey 1-800-344-4539 sells them.

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From: Chris Hand <[email-masked]>
Date: 23 Mar 92 22:25

RFC-822-HEADERS:

==================
> to 1/2 or 2x.  Easier to "warp" the sound source, I guess.

Pinouts looks like this:

	Ground    -| U |- output 2
	clk pulse1-|   |- output 1
	input     -|   |- clock pulse 2
	Vgg       -|___|- Vdd              (MN3207; 1024 stage BBD)

	Ground    -| U |- input
	clk pulse2-|   |- Vgg
	Vdd       -|   |- Clock pulse 1
	           |   |
                   |   |  <-- weird gap
	output 5  -|   |- output 1
	output 5  -|   |- output 2
	output 4  -|___|- output 3	  (MN3011; 3328 stage BBD)

There's also a MN3101 clock generator chip to create the
2-phase clock signal req'd (MN3102 low-voltage chip for
the MN3101).

==> Just for the record, I'm actually on the rend386 mailing
    list, so please don't "cc" messages to me -- I'm getting
    everything twice 8^/ 

Chris