Go Back   Home > Forums > Design & Build > Equipment & Tools

Equipment & Tools From test equipment to hand 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 8th October 2012, 07:52 PM   #601
davada is offline davada  Canada
diyAudio Member
 
Join Date: Jul 2004
Location: Fort St John, BC Canada
Quote:
Originally Posted by dirkwright View Post
So, is this thread going to lead to a definitive "super oscillator" schematic, or is everyone just punting ideas around?
Yes we will come up with a super oscillator.

Eventually.
__________________
David.
  Reply With Quote
Old 8th October 2012, 08:55 PM   #602
diyAudio Member
 
dirkwright's Avatar
 
Join Date: May 2011
Location: Virginia
Quote:
Originally Posted by davada View Post
Yes we will come up with a super oscillator.

Eventually.
Thanks.

Do you expect a group buy on some boards then? I'm just trying to get an idea on where this thread is leading. The goal, in other words.
  Reply With Quote
Old 8th October 2012, 09:07 PM   #603
davada is offline davada  Canada
diyAudio Member
 
Join Date: Jul 2004
Location: Fort St John, BC Canada
Quote:
Originally Posted by dirkwright View Post
Thanks.

Do you expect a group buy on some boards then? I'm just trying to get an idea on where this thread is leading. The goal, in other words.
Well I suppose if one of us makes a break through boards may become available.
You have to clear what you're looking for.

Are you looking for inexpensive medium performance full range or expensive high performance full range? What about a price target?
__________________
David.
  Reply With Quote
Old 9th October 2012, 12:53 AM   #604
diyAudio Member
 
dirkwright's Avatar
 
Join Date: May 2011
Location: Virginia
Quote:
Originally Posted by davada View Post
Well I suppose if one of us makes a break through boards may become available.
You have to clear what you're looking for.

Are you looking for inexpensive medium performance full range or expensive high performance full range? What about a price target?
I like this one:
http://www.users.on.net/~glenk/thd/generator.pdf
which appears to be a variation of Bob Cordell's SVF oscillator.

but I'm willing to build an HP 239A clone (bridge T) also.

So, I guess the former comes under the expensive high performance full range and the latter is less expensive less performance, maybe? Why not both? Why not start with the former and make improvements to it (which I don't have any idea what those would look like)?
  Reply With Quote
Old 9th October 2012, 01:17 AM   #605
davada is offline davada  Canada
diyAudio Member
 
Join Date: Jul 2004
Location: Fort St John, BC Canada
Quote:
Originally Posted by dirkwright View Post
I like this one:
http://www.users.on.net/~glenk/thd/generator.pdf
which appears to be a variation of Bob Cordell's SVF oscillator.

but I'm willing to build an HP 239A clone (bridge T) also.

So, I guess the former comes under the expensive high performance full range and the latter is less expensive less performance, maybe? Why not both? Why not start with the former and make improvements to it (which I don't have any idea what those would look like)?
Okay then put an SVO on a separate board from the AGC and multiplier.
This way you have an option for future modifications.
__________________
David.
  Reply With Quote
Old 9th October 2012, 01:47 AM   #606
diyAudio Member
 
panson_hk's Avatar
 
Join Date: Aug 2005
Blog Entries: 10
Quote:
Originally Posted by dirkwright View Post
So, is this thread going to lead to a definitive "super oscillator" schematic, or is everyone just punting ideas around?
Any definition/requirement for a "super oscillator"?
  Reply With Quote
Old 9th October 2012, 02:22 AM   #607
jcx is online now jcx  United States
diyAudio Member
 
Join Date: Feb 2003
Location: ..
how about a "super multiplier" - one which gvies low harmonics of its diference product frequency output

then quite ordinary oscillators or DACs can feed it frequeny pairs
  Reply With Quote
Old 9th October 2012, 02:34 AM   #608
1audio is offline 1audio  United States
diyAudio Member
 
Join Date: Mar 2004
Location: SF Bay Area
Blog Entries: 2
Default Boonton 1121 AGC circuit

I have attached the Boonton 1121 AGC circuit. This circuit has fast settling and works without any time constant changes from 10 Hz to 140 KHz controlling a SVF oscillator.

Point c is the sine output, point b is the cosine output and point a is the dc voltage back to the AGC element (an analog multiplier in this case). The absolute flatness is in the .01 dB range across its full range. I don't know the settling time but its fast enough to use for swept measurements. An informal test from 500 Hz to 20 Hz showed no obvious change in level.

It may seem complex but all the other solutions are similarly complex and I would guess the cost of an extra wafer on a switch for range caps would not be much less expensive.

The HA2625 opamp is uncompensated and they used the compensation connection to limit the output swing to work with TTL. You would need a separate 5v supply for this circuit.
Attached Images
File Type: jpg 1121 agc circuit.JPG (102.2 KB, 199 views)
__________________
Demian Martin
Product Design Services
  Reply With Quote
Old 9th October 2012, 02:37 AM   #609
1audio is offline 1audio  United States
diyAudio Member
 
Join Date: Mar 2004
Location: SF Bay Area
Blog Entries: 2
Quote:
Originally Posted by jcx View Post
how about a "super multiplier" - one which gvies low harmonics of its diference product frequency output

then quite ordinary oscillators or DACs can feed it frequeny pairs
Do you mean a good double balanced mixer, or a beat frequency oscillator? Beat Frequency Oscillator 700a Equipment General Radio
__________________
Demian Martin
Product Design Services
  Reply With Quote
Old 9th October 2012, 03:27 AM   #610
jcx is online now jcx  United States
diyAudio Member
 
Join Date: Feb 2003
Location: ..
I ws thinking Gilbert Cell multipliers might be better suited to audio - but not certain of practical limits - obviously Spice perfectly matched Q models will give over optimistic results

and what are we practically aiming for -120, -140 dB for < 20? kHz harmonics + IMD, Spurs?? from 24/192 aduio DACs generating input sines in 50-100 kHz range

Last edited by jcx; 9th October 2012 at 03:31 AM.
  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
Radford Low Distortion Oscillator Series 2 audiomik Equipment & Tools 21 19th February 2014 10:46 AM
ultra-low distortion audio oscillator geekysuavo Analog Line Level 16 26th March 2013 03:04 PM
Low distortion oscillator? rjm Equipment & Tools 30 4th May 2011 10:45 PM
Can we improve this low distortion sine oscillator ? gaetan8888 Solid State 22 29th March 2009 12:30 PM
Simple, low distortion 1kHz oscillator jackinnj Solid State 4 6th October 2003 03:58 AM


New To Site? Need Help?

All times are GMT. The time now is 11:54 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