[sdiy] A-440 Reference Oscillator update

[David Brown]

Got my 5.0688 MHz crystals and redid the software.  I put a scope image at
http://modularsynthesis.com/images/DJB-A440-ref-osc.jpg

I want to do some more precise measurements before proceeding.  The 
output is now a 4 V pk-pk sine wave.  I'll keep everyone updated on progress.

Dave

At 09:02 PM 5/23/2006, David Brown wrote:
>Thanks for all the replies. It looks like there is interest in 
>having at least one batch of parts and PCB.  I'm going to do a bit 
>more work on this. One email indicated that I could get even closer 
>in frequency (e.g. exact) by starting with a 5.0688 MHz 
>crystal.  I'm going to give it a try and see how well it works. I 
>have some parts on order that will be here in a couple of weeks.
>
>I'm also going to redo the interface to the Max7401 filter.  I'm 
>driving it rail to rail and minimum distortion is at something like 
>4V pk-pk.  I've got a nice little circuit to attenuate and center 
>the 440 Hz clock and would like to give it a try to minimize THD.  I 
>prototyped a similar circuit and want to experiment more with this.
>
>I'll keep all of your emails and give you an update when I try out 
>the modifications.
>
>Dave