Engineers faced with pressing deadlines and excessive demands for their time may lack the opportunity to participate in continuing education courses at an accredited institution. But most engineers should be able to find the time to investigate a concise course on filter design from Noble Publishing. Entitled "Filter Design By Transmission Zeros," this short course is supplied on a single CD-ROM that will turn just about any personal computer (PC) into a personal RF classroom.
The CD-ROM is divided into 48 course segments. For a computer to properly run the course software, it should be equipped with Version 4 of QuickTime for Windows as well as Adobe Acrobat Reader, although installers for both tools are also included on the CD-ROM. Once loaded, the course can run continuously from segment to segment (and section to section), or a student can use the "Course Outline" section to quickly jump to different segments of the course.
The course's five sessions are Classic Filter Design Review, Transmission Zero Introduction, The Extraction Process, Network Transforms, and Practical Issues. Course narration is clear and well paced, provided by Eagleware (Norcross, GA) founder Randy Rhea, well known for his technical workshops on filter and oscillator design.
The first session includes a brief history of filters; how prototype lowpass-filter designs can be scaled to create other types of filters at higher frequencies, such as bandpass filters; and some of the limitations of designing filters by transforming prototypes. The second session, in contrast, explains how direct synthesis of filter designs supports a variety of topologies and allows the designer to place transmission zeros at precise frequen
The third session details the extraction process for creating a new filter design, showing a conventional extraction sequence along with some general extraction sequences. It then explains how to choose an extraction sequence.
The fourth session highlights network transforms, including how to apply a Norton series transform to the creation of a 70-MHz intermediate-frequency (IF) bandpass filter. The final session provides a detailed example of a lowpass-filter design based on a requirement for a passband of DC to 850 MHz with less than 1-dB passband insertion loss and 12-dB passband return loss. The CD-ROM requires a PC with Windows 95, 98, 2000, or NT, and a Pentium II processor at 333 MHz or faster. Noble Publishing Co., 630 Pinnacle Ct., Norcross, GA 30071; (770) 449-6774, FAX: (770) 448-2839, Internet: www.noblepub.com.