[sdiy] Bunching of MIDI clock messages

[Colin f]

> -----Original Message-----
> From: synth-diy-bounces at dropmix.xs4all.nl 
> [mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Neil Johnson
> Sent: 12 September 2013 13:42
> Subject: Re: [sdiy] Bunching of MIDI clock messages

> Secondly, on the issue of MIDI clock, it sounds like what you 
> need is the software equivalent of a PLL that is slaved to 
> the incoming MIDI clock messages, with a loop filter to 
> reduce the effects of jitter from the remote "reference 
> clock".  If you just treat clock messages as a guide for 
> tempo then that's all you need to do.  Then configure your 
> local PLLed tempo clock to provide whatever sync events you 
> need, and add whatever artificial "slop" you need to recreate 
> what the original instrument had.

That makes for nasty surprises if there is a deliberate change of tempo,
unless you implement some threshold difference in incoming clock period,
above which the filtering is disabled to allow the tempo change to take
effect immediately.

Cheers,
Colin f