4 bit volume attenuator - diyAudio
Go Back   Home > Forums > General Interest > Everything Else

Everything Else Anything related to audio / video / electronics etc) BUT remember- we have many new forums where your thread may now fit! .... Parts, Equipment & Tools, Construction Tips, Software Tools......

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 9th October 2004, 08:08 AM   #1
luvo is offline luvo  Australia
diyAudio Member
 
Join Date: Oct 2004
Default 4 bit volume attenuator

Hi peoples,
I'm after a little guidance on a small problem I have. My radio (Philips FM91) has a 4-bit volume attenuator that has gone wheels-up. It's unrepairable, and I only have a block diagram for it.

i/p--[4dB]---[8dB]---[16dB]---[32dB]-----o/p
| | | |
| | | |
D0 D1 D2 D3


D0-D3
Truth table: 60dB = 1111 (Volume off)
56dB = 0111
52dB = 1011
48dB = 0011

0dB = 0000 (Full volume)


I've read on other forums, people reckon a few resistors chucked into a similar array will suffice? I can't see how. As far as I can tell,
at least four active devices are required to switch in/out each attenuator!!? Anyways, thats easy enough to do, what I'd like to know is - Is there an easier way? Does a logic chip exist that will do what I ask?
This radio is not a high-end audio monster, so quality is not too much of a concern here...
  Reply With Quote
Old 9th October 2004, 02:00 PM   #2
diyAudio Member
 
FLZapped's Avatar
 
Join Date: Oct 2003
Location: Florida
Actually, a 4 bit attenuator gives you 16 steps, that's 17 resistors needed for an L-pad divider.

Can't you find a suitable replacement at someplace like Digikey?

-Bruce
  Reply With Quote
Old 9th October 2004, 09:08 PM   #3
luvo is offline luvo  Australia
diyAudio Member
 
Join Date: Oct 2004
Yes, it is only a 16 step attenuator, using four address bits D0-D3.
Depending on which bits are set low, detemines which attenuators (resistors) are switched into the audio path. ie Set D0 and D1 low = 48dB attenuation.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
relay volume attenuator for PASS pre kiyull Pass Labs 4 26th February 2005 02:56 AM
volume stepped attenuator idea Jamh Chip Amps 22 26th April 2004 03:14 AM
FS: relay volume control attenuator boards jwb Swap Meet 5 30th December 2003 05:24 PM
Volume Control via logrithmic stepped attenuator PaulHilgeman Solid State 4 6th February 2003 11:51 AM


New To Site? Need Help?

All times are GMT. The time now is 07:22 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2