[sdiy] SAD1024 different modes

[Scott Stites]

Hi JH,

I find (d) to be the most intriguing choice.   Easy to do, (no extra parts) and you effectively double your sampling rate with the same clock freq.  The original A/DA flanger used this method, except they mixed all four outputs together.  Mike Irwin (who may be likely to chime in here) designed a clone adaptation that used the parallel mux configuration without mixing all four outputs together (IE, he more closely followed the data sheet example - makes more sense to me, too).  

Cheers,
Scott


-----Original Message-----
From: "JH." <jhaible at debitel.net>
Sent: Aug 29, 2005 11:04 AM
To: diy <synth-diy at dropmix.xs4all.nl>
Subject: [sdiy] SAD1024 different modes

Hi,

I was wondering about the usefullness of the different modes of operation
for
a SAD1024, in the case that I only need 512 stages.

I could

(a) just use one section

(b) connect both sections in parallel (as done in an Electro Harmonix
Flanger)

(c) use both sections with differential amps (data sheet figure 10)

(d) use both sections in parallel/multiplex operation (data sheet figure 9)

The 5th method, serial connection and higer clocking, is not useful for my
application
(physical modeling), because I want the create very short delays, so the
upper
clock rate limit is a factor here.

I guess (a) has no benefits except less loading of the clock generator.

(b) looks trivial - might give 3dB SNR improovement over (a))

(c) is said to give cancellation of even order distortion

(d) most interesing version - but is it the best solution?

Any ideas?

JH.



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