Analog Filter and Linear Circuits Text Plus Kits
What you’ll learn:
- EIM Technologies' Kickstarter campaign ended on April 16, 2025, reaching ~$108,000 in pledges. The book and associated kits can now be ordered from EIM directly, with details below.
- EIM used Kickstarter to introduce a new textbook on analog filter and linear circuits design—its contents are provided in this article.
- Kits of parts and circuit boards, associated with the book, are available as optional add-ons.
- Take our "Skills and Knowledge" poll.
About a year ago, Electronic Design covered a successful $112,000 Kickstarter campaign by the team at EIM (Evo-in-motion) Technology, which offered a 300-page how-to book, Fundamental Analog Circuits and Semiconductors.
The circuits in the book were described for implementation using modern breadboarding techniques. Breadboard-friendly power supplies and rudimentary test-and-measurement equipment and kits of components were available to accompany the book, too. Fundamental Analog Circuits and Semiconductors, and the optional accompanying kit, can be found on the EIM website.
EIM Technology was no stranger when it comes to Kickstarters featuring educational kits, now successfully funding 14 out of 15 campaigns. Campaign number 15 opened at the time this article was written [Update: It's now closed, but items can be ordered from EIM, per below] and should be of interest to many of Electronic Design’s readers. EIM’s book, Fundamental[sic] of Analog Filter Design – An Experimental Discovery of Signals, Mathematics and Linear Circuits, was available for $89CAD in the campaign.
Kits of parts and boards, associated with the book, are also [no longer] available in the Kickstarter, with pledges that starting at an additional $90CAD. They included:
- A bag of components containing resistors, trim pots, capacitors, inductors, and op amps that are needed to work on the experiments in the book
- A set of customized PCB modules to implement the projects in the book
- A full-sized breadboard for hands-on prototyping
- Accessory parts (cables, connectors, six electrodes for the ECG project)
To get these at a discount, be aware that EIM’s Kickstarter campaign, found here, closed on Wed., April 16. 2025, at 6:05 PM PDT. The Kickstarter items can now be ordered directly from EIM, here.
What follows is a summary of the contents of the book:
Chapter 1: Introduction to Analog Signals and Filters
This chapter lays the foundation for understanding analog signals and filter circuits. It introduces the essential concepts that will be used throughout the book and in practical applications.
1.1 Basics of Analog Signals
- Difference between analog and digital signals
- Characteristics of analog signals: frequency, amplitude, phase
- Examples of real-world analog signals (audio, biomedical, and communication signals)
1.2 Basics of Analog Filters
- What filters do: separating, enhancing, or suppressing signals
- Types of analog filters: low-pass, high-pass, band-pass, and band-reject
- Common applications of filters in audio, communication, and biomedical systems
1.3 Useful Software and Tools
- Introduction to LTSpice for circuit simulation
- MATLAB and Python for signal processing
- How to use an oscilloscope and function generator for experiments
1.4 Laboratory Skills
- Breadboarding and soldering techniques
- Measuring and analyzing signals with an oscilloscope
- Debugging circuits and common troubleshooting techniques
Chapter 2: Mathematical Foundations for Signal Processing
This chapter provides essential mathematical tools to understand and analyze signals and systems. The focus is on making complex concepts approachable through visualizations and practical examples.
2.1 Complex Numbers and Signal Representations
- Understanding imaginary numbers and complex exponentials
- Euler’s formula and its significance in engineering
- Representing signals using phasors
2.2 Signal Transformations
- Time-domain vs. frequency-domain analysis
- Fourier Transform basics: breaking down signals into frequency components
- Laplace Transform: analyzing systems in the s-domain
2.3 System Modeling in Frequency Domain
- Understanding transfer functions
- Poles and zeros of a system and their impact on system behavior
- Bode plots for frequency response analysis
2.4 System Response in Time-Domain
- Impulse response and step response of filters
- Convolution and its role in signal processing
- Stability criteria for analog circuits
Chapter 3: Passive Filters and Their Realizations
This chapter explores the fundamental building blocks of analog filters—passive components like resistors, capacitors, and inductors. You will learn how to analyze, simulate, and build these filters.
3.1 Low-Pass, High-Pass, Band-Pass, and Band-Reject Filters
- Definition and working principles of each filter type
- Practical use cases for each filter (audio processing, radio tuning, noise reduction)
3.2 Frequency Response and Transfer Functions
- Derivation of transfer functions for first-order and second-order filters
- Understanding cutoff frequency, bandwidth, and roll-off rate
3.3 Circuit Implementations and LTSpice Simulations
- Designing and analyzing passive filters using LTSpice
- Comparing real-world results with theoretical calculations
- Practical circuit construction on breadboards
Chapter 4: Active Filters and Circuit Implementations
This chapter introduces active filters, which use operational amplifiers (op amps) to achieve better performance and flexibility in signal processing.
4.1 Review of Operational Amplifiers
- Understanding op-amp basics: inverting and non-inverting configurations
- Op-amp parameters: gain, bandwidth, slew rate, and input/output impedance
4.2 Active LPF, HPF, BPF, BRF, and All-Pass Filters
- Advantages of active filters over passive filters
- Second-order and higher-order active filter designs
- Real-world applications of active filters in instrumentation and communication
4.3 Filters with Generalized Impedance Converters (GIC)
- Introduction to GIC-based filter design
- How GICs enable precise high-order filter implementation
- Practical circuits using GICs for superior performance
Chapter 5: Advanced Topics in Filter Design
This chapter explores more sophisticated filtering techniques for specialized applications.
5.1 Higher-Order Filters
- Cascading multiple filter stages to achieve sharper roll-offs
- Understanding the relationship between filter order and frequency response
5.2 Butterworth Filters
- Designing maximally flat response filters
- Comparison with Chebyshev and Bessel filters
- MATLAB/Python-based simulations for Butterworth filter design
5.3 LC Filters and Advanced CAD-Based Design
- Understanding LC filters: why inductors are used and how they affect performance
- Applications of LC filters in RF and power electronics
- Using circuit design software for professional filter design
Chapter 6: Tangible Projects
This chapter brings theory into practice with real-world applications of signal processing and filters.
6.1 Project 1: Waveform Transformation (Using Low-Pass Filters)
- Converting square waves into sinusoidal signals using LPF
- Visualizing frequency content using Fourier analysis
- Practical demonstration with an oscilloscope
6.2 Project 2: Audio Signal Processing (Bass & Treble Enhancer)
- Designing an equalizer circuit to modify audio signals
- Implementing and testing bass boost and treble enhancement
- Understanding how human hearing perceives different frequency ranges
6.3 Project 3: ECG Signal Processing (Acquisition & Filtering)
- Building a simple electrocardiogram (ECG) circuit
- Using filters to remove noise and extract heart signals
- Understanding biomedical signal processing basics
Andy's Nonlinearities blog arrives the first and third Monday of every month. To make sure you don't miss the latest edition, new articles, or breaking news coverage, please subscribe to our Electronic Design Today newsletter. Please also subscribe to Andy’s Automotive Electronics bi-weekly newsletter.
About the Author
Andy Turudic
Technology Editor, Electronic Design
Andy Turudic is a Technology Editor for Electronic Design Magazine, primarily covering Analog and Mixed-Signal circuits and devices. He holds a Bachelor's in EE from the University of Windsor (Ontario Canada) and has been involved in electronics, semiconductors, and gearhead stuff, for a bit over a half century.
"AndyT" brings his multidisciplinary engineering experience from companies that include National Semiconductor (now Texas Instruments), Altera (Intel), Agere, Zarlink, TriQuint,(now Qorvo), SW Bell (managing a research team at Bellcore, Bell Labs and Rockwell Science Center), Bell-Northern Research, and Northern Telecom and brings publisher employment experience as a paperboy for The Oshawa Times.
After hours, when he's not working on the latest invention to add to his portfolio of 16 issued US patents, he's lending advice and experience to the electric vehicle conversion community from his mountain lair in the Pacific Northwet[sic].
AndyT's engineering blog, "Nonlinearities," publishes the 1st and 3rd monday of each month. Andy's OpEd may appear at other times, with fair warning given by the Vu meter pic.