electro-music.com   Dedicated to experimental electro-acoustic
and electronic music
 
    Front Page  |  Articles  |  Radio
 |  Media  |  Forum  |  Wiki  |  Links  |  Store
Forum with support of Syndicator RSS
 FAQFAQ   CalendarCalendar   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   LinksLinks
 RegisterRegister   ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in  Chat RoomChat Room 
Live streaming at radio.electro-music.com

  host / artist show at your time
<on air> Rob Adventures in Sound
Please visit the chat
 Forum index » Clavia Nord Modular » G2 Building Blocks
Variable Clock Generator Gate Pulse Width Output
Post new topic   Reply to topic Moderators: Nord Modular Editors
Page 1 of 1 [6 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
varice



Joined: Dec 29, 2004
Posts: 725
Location: Northeastern shore of Toledo Bend
Audio files: 22
G2 patch files: 49

PostPosted: Mon Apr 16, 2012 8:27 pm    Post subject: Variable Clock Generator Gate Pulse Width Output
Subject description: with a duty cycle that remains constant with tempo change
Reply with quote  Mark this post and the followings unread

Here is a little patch trick that I have been using to stretch the very short trigger output of the Clock Generator module into a longer gate signal. The neat part of this particular trick is using a specially configured Decay Envelope module to modulate the time parameter of a Logic Delay module. This configuration results in the clock gate pulse duty cycle output of the Logic Delay module remaining relatively constant over the full range of the Clock Generator module tempo settings.

A problem though is that the time modulation control setting of the Logic Delay module will result in a non-linear pulse width setting (e.g. setting this Logic Delay control at the mid point results in a clock pulse duty cycle that is much less than 50/50 as may be desired). A more linear pulse width control is accomplished by adding a Constant Level module (in unipolar mode) patched through a Static Shaper module (in Inv x2 mode) connected to the AM input of the EG module. With this more linear control at any tempo setting:

1. A Control Level value of 64 results in the maximum gate pulse width.
2. A value of 48 gives an approximate 75/25 duty cycle for the Gate PW, which is about the standard duration of a note in musical notation.
3. A value of 32 gives an approximate 50/50 duty cycle Gate PW.
4. A value of 0 gives the minimum Gate PW.

Another issue is that when increasing the Clock tempo from very slow to faster BPM rates with the Gate PW set to max, a new Clock pulse can occur before the Logic Delay has timed out and the output goes low. This results in an expected Clock trigger being missed. The Flip Flop and AND Gate logic modules are patched in a way to force a gate retrigger with every Cock pulse even if the Logic Delay has not timed out.

If you don’t need linear Gate PW control and forced gate retrigger with tempo increases, a minimal version of this patch trick would be to use only the EG and Logic Delay modules with the Clock, adjusting only the modulation time parameter of the Logic Delay module to set the clock gate pulse width. The other parameters of the EG and Delay modules should not be changed.


Clock Gate PW2.pch2
 Description:
Variable Clock Generator Gate Pulse Width Output with a duty cycle that remains constant with tempo change

Download
 Filename:  Clock Gate PW2.pch2
 Filesize:  3.32 KB
 Downloaded:  317 Time(s)


_________________
varice

Last edited by varice on Tue Apr 17, 2012 3:13 pm; edited 2 times in total
Back to top
View user's profile Send private message
iPassenger



Joined: Jan 27, 2007
Posts: 1051
Location: Sheffield, UK
Audio files: 5
G2 patch files: 78

PostPosted: Tue Apr 17, 2012 10:23 am    Post subject: Reply with quote  Mark this post and the followings unread

Why the envelope?

What about this: Attached.

You use one pulse to extract the leading edge (so the tempo doesn't affect note length) and then the second pulse to set the length.


clock_gate_pw2_447[1].pch2
 Description:

Download
 Filename:  clock_gate_pw2_447[1].pch2
 Filesize:  2.97 KB
 Downloaded:  332 Time(s)


_________________
iP (Ross)
- http://ipassenger.bandcamp.com
- http://soundcloud.com/ipassenger
Back to top
View user's profile Send private message Visit poster's website
varice



Joined: Dec 29, 2004
Posts: 725
Location: Northeastern shore of Toledo Bend
Audio files: 22
G2 patch files: 49

PostPosted: Tue Apr 17, 2012 1:42 pm    Post subject: Reply with quote  Mark this post and the followings unread

Sorry for the confused wording of the first paragraph of the first post. I have edited it to hopefully be clearer.

In other words, I want the pulse width out of the Logic Delay to change to match any tempo change (that’s why the EG is modulating the Delay time). This will give a relatively constant duty cycle (ratio of gate on to gate off) with any tempo.

_________________
varice
Back to top
View user's profile Send private message
iPassenger



Joined: Jan 27, 2007
Posts: 1051
Location: Sheffield, UK
Audio files: 5
G2 patch files: 78

PostPosted: Tue Apr 17, 2012 2:34 pm    Post subject: Reply with quote  Mark this post and the followings unread

Ah sorry, I see what you mean. Smile Wasn't paying enough attention. Embarassed
_________________
iP (Ross)
- http://ipassenger.bandcamp.com
- http://soundcloud.com/ipassenger
Back to top
View user's profile Send private message Visit poster's website
varice



Joined: Dec 29, 2004
Posts: 725
Location: Northeastern shore of Toledo Bend
Audio files: 22
G2 patch files: 49

PostPosted: Tue Apr 17, 2012 3:18 pm    Post subject: Reply with quote  Mark this post and the followings unread

No, it was my fault for incorrectly stating that the pulse width instead of the duty cycle remained consistent with tempo changes. Even the wording in the patch name bars and textpad was wrong! Embarassed I have just now replaced the patch in the original post.
_________________
varice
Back to top
View user's profile Send private message
varice



Joined: Dec 29, 2004
Posts: 725
Location: Northeastern shore of Toledo Bend
Audio files: 22
G2 patch files: 49

PostPosted: Tue May 08, 2012 7:56 pm    Post subject: Reply with quote  Mark this post and the followings unread

Here are two new versions. These use a ZeroCnt module instead of an EG for more accurate clock rate to control signal conversion. (Thanks Ross!) ref:

http://electro-music.com/forum/topic-53307.html

The “c” version has a much more linear control setting of the clock duty cycle.


Clock Gate PW2b.pch2
 Description:

Download
 Filename:  Clock Gate PW2b.pch2
 Filesize:  3.2 KB
 Downloaded:  327 Time(s)


Clock Gate PW2c.pch2
 Description:
Linear control of Clock Duty Cycle

Download
 Filename:  Clock Gate PW2c.pch2
 Filesize:  3.39 KB
 Downloaded:  327 Time(s)


_________________
varice
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic Moderators: Nord Modular Editors
Page 1 of 1 [6 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
 Forum index » Clavia Nord Modular » G2 Building Blocks
Jump to:  

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
e-m mkii

Please support our site. If you click through and buy from
our affiliate partners, we earn a small commission.


Forum with support of Syndicator RSS
Powered by phpBB © 2001, 2005 phpBB Group
Copyright © 2003 through 2009 by electro-music.com - Conditions Of Use