Contents
Tuned Radio-Frequency (TRF) Radios
Circuit Description of a TRF Radio
Block Diagram of a Regenerative Radio
Circuit Description of a Regenerative Radio
Block Diagram of a Reflex Radio
Circuit Description of a Reflex Radio
Block Diagram of a Superheterodyne Radio
Circuit Description of a Superheterodyne Radio
Software-Defined Radio Front-End Circuits
Block Diagram of a Software-Defined Radio Front End
Description of Front-End Circuits for a Software-Defined Radio System
Comparison of the Types of Radios
CHAPTER 2 Calibration Tools and Generators for Testing
Radio Frequency (RF) Spectrum Analyzers
Where to Buy the Tools and Test Equipment
CHAPTER 3 Components and Hacking/Modifying Parts for Radio Circuits
CHAPTER 4 Building Simple Test Oscillators and Modulators
The Amplitude-Modulated Signal
First Project: A CW RF Test Oscillator
Modulator Circuit for the CW Generator
CHAPTER 5 Low-Power Tuned Radio-Frequency Radios
Design Considerations for TRF Radios
Improving Sensitivity and/or Selectivity via Antenna Coils or Circuits
Variation of the Design (Alternate Design of the TRF Radio)
CHAPTER 6 Transistor Reflex Radios
Motivation Behind Amplifying Both Radio-Frequency and Audio-Frequency Signals
One-Transistor TRF Reflex Radio
Multiple-Transistor Reflex Radio Circuit
CHAPTER 7 A Low-Power Regenerative Radio
Improving Sensitivity by Regeneration
Improving Selectivity by Q Multiplication via Regeneration
Design Considerations for a Regenerative Radio
CHAPTER 8 Superheterodyne Radios
Commercially Made Transistorized Superheterodyne Radios
A Four-Transistor Radio Schematic
Alternative Oscillator and Antenna Coil Circuit
CHAPTER 9 Low-Power Superheterodyne Radios
Low-Power Oscillator, Mixer, and Intermediate-Frequency Circuits
Low-Power Detector and Audio Circuits
“First” Design of a Low-Power Superheterodyne Radio
Alternative Low-Power Superheterodyne Radio Design
Photos of Low-Power AM Superheterodyne Radios
CHAPTER 10 Exotic or “Off the Wall” Superheterodyne Radios
A One-Transistor Superheterodyne Radio
Design Considerations for a One-Transistor Superheterodyne Radio
A Two-Transistor Superheterodyne Radio
CHAPTER 11 Inductor-less Circuits
Gyrators (aka Simulated or Active Inductors)
Inductor-less (aka Coil-less) Superheterodyne Radio
CHAPTER 12 Introduction to Software-Defined Radios (SDRs)
SDR Front-End Circuits, Filters, and Mixers
Phasing Circuits for 0- and 90-Degree Outputs for I and Q Signals
Multipliers for Generating 0- and 90-Degree Phases
Example Radio Circuits for Software-Defined Radios
Second SDR Front-End Circuit for the 40-Meter Amateur Radio Band
CHAPTER 13 Oscillator Circuits
CHAPTER 14 Mixer Circuits and Harmonic Mixers
Adding Circuits Versus Mixing Circuits
Distortion Can Be a Good Thing (for Mixing)
Single-Bipolar-Transistor Distortion
Simple Transistor Mixer and Its Conversion Transconductance
CHAPTER 15 Sampling Theory and Sampling Mixers
Sampling Signals as a Form of Muliplication or Mixing
Multiplexer Circuits as Balanced Mixers
Tradeoffs in Performance of the Mixers
CHAPTER 16 In-Phase and Quadrature (IQ) Signals
Introduction to Suppressed-Carrier Amplitude Modulation
How I and Q Signals Are Generated
I and Q Signals Used in Software-Defined Radios (SDRs)
CHAPTER 17 Intermediate-Frequency Circuits
Considerations of Distortion Effects on IF Amplifiers
CHAPTER 18 Detector/Automatic Volume Control Circuits
IQ Detectors for AM Broadcast Signals
Measuring an Average Carrier or Providing Automatic Volume Control
Introduction to Operational Amplifiers
Connecting Multiple Amplifiers for an Amplifier System
Practical Considerations for Using Amplifiers
Simple Parallel and Series Resonant Circuits
Resonant Circuits in Oscillators
Examples of Band-Pass and Band-Reject Filters
Methods to Reduce the Amplitude of the Image Signal
Analysis of an Image-Rejection Mixer Using I and Q Signals
Analysis of the Image-Reject Mixer
Consequences of an Imperfect 90-Degree Phase Shifter on Reducing the Image Signal
Sources of Random Electronic Noise and Some Basic Noise Theory
Paralleling Transistors for Lower Noise
Differential-Pair Amplifier Noise
Update on the One-Transistor Superheterodyne Radio
Comments on SDR 40-Meter Front-End Circuit
Experimenting with Mixers and Using the Spectran Spectrum Analyzer Program
Conducting Experiments on Op Amps and Amplifiers
Experiments with a Resonant Circuit
Some Final Thoughts on the Book
APPENDIX 2 Inductance Values of Oscillator Coils and Intermediate-Frequency (IF) Transformers
APPENDIX 3 Short Alignment Procedure for Superheterodyne Radios