electro-music.com   Dedicated to experimental electro-acoustic
and electronic music 		 
    Front Page  |  Radio
 |  Media  |  Forum  |  Wiki  |  Links
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 
go to the radio page Live at electro-music.com radio 1 Please visit the chat
  host / artist show at your time
today> Twyndyllyngs - not cancelled tonight Chez Mosc
poster

 Forum index » DIY Hardware and Software » Developers' Corner
Filter design using the LTC1562-2
Post new topic   Reply to topic Moderators: DrJustice
Page 1 of 1 [4 Posts]		 View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
metacohl



Joined: Jul 26, 2010
Posts: 25
Location: Oakland, ca
PostPosted: Thu Jul 29, 2010 12:41 pm    Post subject: Filter design using the LTC1562-2 Reply with quote  Mark this post and the followings unread
Does anyone have experience using this chip for audio?
here is the datasheet http://cds.linear.com/docs/Datasheet/15622fa.pdf

Its marketed for radio frequencies, but I am trying to figure out if it can be adapted for audio. The data sheet provides diagrams for chebyshev, butterworth, and other filter types.
Back to top
View user's profile Send private message
metacohl



Joined: Jul 26, 2010
Posts: 25
Location: Oakland, ca
PostPosted: Thu Jul 29, 2010 12:57 pm    Post subject: Reply with quote  Mark this post and the followings unread
looking at the data sheet it says that

f0=200khz(sqrt((7958Ohm)/R2)) for one of the filter arrangements

sooo... f0=20khz R2= 795800 Ohms?

So maybe a trimming resistor and a POT in series if you wanted to have a usable f0 range under 20khz?
Back to top
View user's profile Send private message
blue hell
Site Admin


Joined: Apr 03, 2004
Posts: 24587
Location: The Netherlands, Enschede
Audio files: 309
G2 patch files: 320
PostPosted: Thu Jul 29, 2010 1:17 pm    Post subject: Reply with quote  Mark this post and the followings unread
metacohl wrote:
f0=20khz R2= 795800 Ohms?


Yes, or, 0.8 Meg ... so 80 Meg for 2 kHz .. Resistance that large will mean that when you breathe over the circuit f0 will go all the way ... not very usable for the audio range.

I see tho that the internal capacitor is between INV and V1 being both accessible from the outside - maybe you could add some extra capacitance there to help f0 down .. stability may be an issue then or it may blow up under certain conditions.
_________________
Jan
also .. could someone please turn down the thermostat a bit.
Posted Image, might have been reduced in size. Click Image to view fullscreen.
Back to top
View user's profile Send private message Visit poster's website
metacohl



Joined: Jul 26, 2010
Posts: 25
Location: Oakland, ca
PostPosted: Thu Jul 29, 2010 1:26 pm    Post subject: Reply with quote  Mark this post and the followings unread
Blue Hell wrote:
metacohl wrote:
f0=20khz R2= 795800 Ohms?


Yes, or, 0.8 Meg ... so 80 Meg for 2 kHz .. Resistance that large will mean that when you breathe over the circuit f0 will go all the way ... not very usable for the audio range.

I see tho that the internal capacitor is between INV and V1 being both accessible from the outside - maybe you could add some extra capacitance there to help f0 down .. stability may be an issue then or it may blow up under certain conditions.


Ahh yes, I did not really think about what a absurdly high resistance that is. You might be right about adding more capacitance between INV and V1. I'd have to do some math to figure out the implementation of that and, like you said, any possible issues that might arise from that implementation.

Maybe someone else can confirm this?
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic Moderators: DrJustice
Page 1 of 1 [4 Posts]		 View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
 Forum index » DIY Hardware and Software » Developers' Corner
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


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