« Voltage Multiplier Rise Time - John Dunn, Consultant, Ambertec, P.E., P.C. | Main | Making the Turbines Spin - Dick LaRosa »

March 03, 2011

Comments

George Storm

Too true. The second-order filter is an optimum zero-overshoot design. Perhaps it would be even nicer to use the extra pole to make a third-order equivalent?

Paul Rako

This is a stopband leakage problem. C1 will pass very high frequencies directly to the output. You can fix it by feeding C1 with a buffer amp from the output. See
edn.com/article/459456-Eliminate_Sallen_Key_stopband_leakage_with_a_voltage_follower.php

John Dunn

Stopband leakage arises because C1 does indeed pass high frequencies directly to the output of U1A, but adding a buffer for feeding back to C1 would still require that buffer to be infinitely fast to accomodate a zero-rise-time input from V3. The symptom could be diminished, but not eliminated.

Ralph Williams

This reminds of the issue of slew-induced distortion versus bandwidth limiting when oversampled audio DAC's interface to analog circuitry. Presumably one of the advantages of vacuum tubes is that they bandwidth limit before they slew-rate limit.

Verify your Comment

Previewing your Comment

This is only a preview. Your comment has not yet been posted.

Working...
Your comment could not be posted. Error type:
Your comment has been saved. Comments are moderated and will not appear until approved by the author. Post another comment

The letters and numbers you entered did not match the image. Please try again.

As a final step before posting your comment, enter the letters and numbers you see in the image below. This prevents automated programs from posting comments.

Having trouble reading this image? View an alternate.

Working...

Post a comment

Comments are moderated, and will not appear until the author has approved them.

Your Information

(Name and email address are required. Email address will not be displayed with the comment.)

Editor

  Learn about our  

 free engineering 

consulting referral 

      service at:

 

  IEEE Consultant's 

      Network of 

     Long Island

 

We have over forty 

electrical, electronic, 

mechanical and 

software engineers 

with expertise in more 

than sixty-five categories 

of technology and business. 

All are members of the 

IEEE and adhere to the 

IEEE professional codes 

of ethics. 

No fee is charged for the

referral service. 

Each member is an 

independent consultant 

and negotiates his/her 

own consulting agreement.

 

Editor: Jerry Brown

Contributors:

John Dunn

Marty Kanner

Murray Kleiner

Dick LaRosa

David Pinkowitz

Carl Schwab

Gerry Bodner

Larry Rachman

 

Unless otherwise noted, 

reprinting or republication 

of anarticle on this blog is 

authorized by crediting the 

author and prominently 

displaying the following 

sentence at the beginning 

or end of the article,

including the hyperlink to

IEEE Consultant's Network 

of Long Island


"This report is republished 

with permission of IEEE 

Consultant's Network of 

Long Island"

 

Pages

Blog powered by Typepad

Enter your email address:

Delivered by FeedBurner