Getting Started with a Radio Design
||Martin Stoehr, Principal Member of the Technical Staff, Applications
Abstract: The process of designing a radio system can be complex and often involves many project tradeoffs. With a little insight, balancing these various characteristics can make the job of designing a radio system easier. This tutorial explores these tradeoffs and provides details to consider for various radio applications. With a focus on the industrial, scientific, medical (ISM) bands, the subjects of frequency selection, one-way versus two-way systems, modulation techniques, cost, antenna options, power-supply influences, effects on range, and protocol selection are explored.
Selecting the Right Frequency
Why would a designer want to operate in the 868MHz/915MHz band rather than the 433.92MHz part of the spectrum? In other words, how do you choose which frequency to use? The answer is affected by two primary considerations: either the application has a traditional and/or predefined band in which it operates, or the designer must balance the tradeoffs of each parameter in the design to make the best band selection (Figure 1).
Figure 1. Common radio design trade-offs.