[sdiy] 24 --> 48 PPQ double clock pulse

[media.nai at rcn.com]

>     Hi everyone, I just subscribed again after a few years. Is the  list
>still active? 


Yes :)

>This list helped me great in the past and now i have a
>question.   Last week a bought a Linndrum and already like  it alot. To
>sync it to other devices there is a clock in and out. I allready  found
>out it runs on 48 PPQ (pulses per quarter measure). My problem is that the
>rest of my drummachines run on 24 PPQ (roland boxes) so i would like to
>double  the pulse rate.   Is there a simple circuit that can do this?   I
>thought of something that outputs a pulse on the  start and end of the
>24PPQ pulse but i don't know how to implement this.  Are there any other
>(better) alternatives?    Any help would be much appreciated.   Thanks in
>advance. Greetings, Eric (Amsterdam)  

You can build one rather inexpensively using a 4047 and two RC
differentiators, so it triggers the 4047 at both edges.  The differentiator
going towards the positive trigger (pin 8) has a diode facing that
direction in parallel with the resistor, the differentiator going towards
the negative trigger (pin 6) has a diode facing the other direction in
parallel with the resistor.  I'd try values of 1K and 100pF and see if that
works.