March 2011

Doc ID 17543 Rev 2

1/6

AN3218

Application note

Adjacent channel rejection measurements

for the STM32W108 platform

1

Introduction

This application note describes a method which could be used to characterize adjacent

channel rejection (ACR) on RF chips. It also compares different methods used by other

manufacturers when quoting ACR performance.

Adjacent channel rejection (ACR) is an important parameter for any radio receiver. It is a

measure of how well a receiver performs on its frequency channel when there is an

interfering system in the vicinity operating on a nearby channel.

ACR is generally one of the parameters that is used to compare the performance of different

RF ICs. However, different silicon vendors use different methods for measuring ACR, which

may distort performance figures.

This application note presents a method used to measure ACR on its IEEE 802.15.4-2003

compliant ICs, and compares it against other methods.

1.1

Supported STM32W108xx kits

This document is applicable to the following STM32W108xx kits:

●

STM32W108xx starter kit (part number: STM32W-SK)

●

STM32W108xx extension kit (part number: STM32W-EXT)

●

STM32W108xx low-cost RF control kit (part number: STM32W-RFCKIT)

2

Requirements

The IEEE 802.15.4-2003 standard specifies a minimum level of ACR that chips must meet.

It is defined as follows:

6.5.3.4 Receiver jamming resistance

The minimum jamming resistance levels are given in Table 22. The adjacent channel is

one on either side of the desired channel that is closest in frequency to the desired

channel, and the alternate channel is one more removed from the adjacent channel.

For example, when channel 13 is the desired channel, channel 12 and channel 14 are

the adjacent channels, and channel 11 and channel 15 are the alternate channels.

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