Customer Reviews

Active Filter Cookbook, Second Edition

5 star:		(8)
4 star:		(0)
3 star:		(1)
2 star:		(0)
1 star:		(0)

 

 

Owners of Lancaster's original Active Filter Cookbook: read on. I just bought Lancaster's Active Filter Cookbook, Second Edition. For years I have owned a copy of the original (1975) edition (mine is the 17th (1992) SAMS reprinting). Based on a cursory inspection, I can find no difference between the 1992 reprinting of the original edition and the so-called second edition. The Preface, the Table of Contents, the page numbering, the contents of numerous pages I examined, the List of References, the Index, are all identical, as far as I can tell. There is no new preface to the second edition. There is no description, either inside or on the outside cover, of what has been changed in the second edition. Based on my examination, I would recommend that, if you already own a copy of the first edition, there is no reason to buy the second.

I bought the second edition cookbook in the early '90s. I have used Mr. Lancasters' book to design many audio active filters. I am ordering another copy of the "Active Filter Cookbook" because I gave away my other copy to an engineer in Asia (while on a business trip) who desparately needed it. The math is kept to a minimum, but very accurate if good quality parts (Op-Amps, resistors, caps etc) are used. Each chapter is dedicated to a specific topic, which makes reading very easy. Mr. Lancaster arms the reader with the tools neccessary to understand, build and/or modify existing designs. I would only recommend this book to readers who have built previous projects, as Mr. Lancaster does not go into any construction details/techniques.

I have used this book to design many active filters for audio applications. The book is non-mathematical in nature, many design tables are given, but most importantly the book connects theory and real world applications. Many other books are way too theoretical in nature to be of any use. If you want to build filter circuits, then this book is a must. If you want lots of elegant mathematics, look elsewhere. An excellent book.

The design of electronic filters is usually seen as a complex and difficult task, best handled by specialists. Don Lancaster, with this durable treatise, has written a clear and easy to follow guide. The principles and mathematics at the root of this subject are not trivialised but are explained in such a way that the non-specialist will have little trouble achieving success.

Owners of Lancaster's original Active Filter Cookbook: read on. I just bought Lancaster's Active Filter Cookbook, Second Edition. For years I have owned a copy of the original (1975) edition (mine is the 17th (1992) SAMS reprinting). Based on a cursory inspection, I can find no difference between the 1992 reprinting of the original edition and the so-called second edition. The Preface, the Table of Contents, the page numbering, the contents of numerous pages I examined, the List of References, the Index, are all identical, as far as I can tell. There is no new preface to the second edition. There is no description, either inside or on the outside cover, of what has been changed in the second edition. Based on my examination, I would recommend that, if you already own a copy of the first edition, there is no reason to buy the second.

There's a lot to be said in favor of this book, I must acknowledge right up front. It does contain quite a few tabulated filter designs, and Mr Lancaster teaches a fairly straightforward approach to selecting from among them and scaling them to fit the user's needs. The print quality is good, too.

On the other hand, it is a less complete book than I remembered it being from the days when I could still find my original copy. There are some gaps in treatment of notch filters, for instance, and less thorough coverage of some other types than I would have liked. I'm also not sure why he shunned everyday filter terminology like "Butterworth" and "ripple" in favor of dumbed-down alternatives like "flattest response" and "dips." And, being yet another reprint of the Second Edition, there has been no effort to update information on better op-amps that are available now, or to modernize the active filter applications that wrap up the book.

Add to that the downright HEFTY price tag for this relatively slim reprint! Taking those reasons together, if I'd had the opportunity to glance through this volume in a store before buying, I probably wouldn't have done so. I ordered it more for sentimental reasons than anything else, but now that I can once again see its limitations for myself, I realize I would have been far better off putting that money toward a newer filter design book, such as the latest edition of Williams and Taylor.

On the other hand, if you need the easy to use cookbook kind of information this book contains, and you do not foresee buying more than one book on the subject of active filters any time soon, then this book might very well be worth the price to you. What it DOES contain would be hard to find in any single other book. You'd probably have to search through two or three other works, and who knows how much you'd spend doing that.

So, bottom line, I think it's fair to say that if you're looking for an all-in-one general resource on electronic filters, this is the one to have despite the price. But if you already have some other filter handbooks and a background in the subject, this one might not be a very good dollar value for you.

A great book for filter design and analysis. This book has been a great help in understanding the detailed aspects of multiple filter types.

Don Lancaster is a very good writer, and has focussed on what really matters for anyone designing analogue active filters. At 240 pages, this book has all the design guidelines, mathematics and practical tips for the popular single-amplifier biquad (SAB) circuits such as Sallen-Key and Multiple-FeedBack (MFB), and 3- or 4-opamp circuits such as State-Variable designs; it covers cascading multiple sections, with many practical examples up to 6th order filters; it covers bandpass, low-pass and high-pass active filters, plus "just enough" mention of notch and Cauer/elliptical filters, as well as filter applications and digital tuning, etc... but the edition I have - the 1995 - is a bit too old to cover some of the more recent developments. No mention of switched-capacitor filters (well, the MF10C has come and gone in popularity, so no problem there), but no mention of any digital filter techniques... even so, you probably want that in a separate book; this remains a good introduction, very useful as it is, providing an extremely good grounding in theory - such as damping (transitional Thompson-Butterworth an all that), normalization/scaling, "s-plane" equations, etc. The practical side is fully covered (e.g. "You can NOT build a stable, high-Q, easy-to-tune, single-[amplifier] bandpass filter"); sensitivity of component variation is covered well.

The book is physically and conceptually the "right size" - with no "waffle"; many university textbooks may be larger, and cover a few obscure extra filter circuits, but 90% of designers will never need them in their work. It is much more useful than (although covers les filter types, and slightly less up-to-date than) Lenk's "Simplified Design of Filter Circuits", which is about the same size.

It would be nice to see a new edition (although I am happy enough with what the 1995/6 edition has); it could be improved slightly by having some of the alternative/family names for filter circuits (such as KRC and VCVS) listed, and a few (very few) extra comments could be made as to why you would avoid certain circuits. It would also be nice if a bit of colour was used to clarify some diagrams, and perhaps have the chapter and subsection heading repeated at the top of each page. All that is relatively unimportant - basically: don't mess with perfection, this book would be worse if it tried to cover much more than it does (but it would be nice to see an end to the CD4016 being called a "new" development).

Needed this book for an online class and now that class is over, it has found a place on the bench with just a few others.