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Investigating BluetoothTM Modules:
The First Step in Enabling Your
Device with a Wireless Link
Application Note 1333-2
Introduction
Note: This Application Note is designed for
vendors or manufacturers who plan to add
Bluetooth is an innovative new tech- Bluetooth operates in the 2.4 GHz
a wireless link to their products by installing nology that provides wireless connec- ISM (Industrial, Scientific, and
commercially-available, pre-built Bluetooth tivity to a growing variety of electron- Medical) band, an unlicensed portion
ic devices--computers, laptops, of the spectrum that is already well-
modules into them. It is addressed to a Personal Digital Assistants (PDAs), used. Not only do microwave ovens
wide audience working in electronics peripherals, cameras, cellular operate within this range, but other
phones, pagers, and wireless head- RF communications technologies as
whose knowledge and skills may vary, but sets. Even use with home appliances well, most notable of which are
assumes no specific knowledge of RF such as refrigerators has been HomeRF and IEEE 802.11b. Because
explored. With Bluetooth technology, this spectrum is unlicensed, even
(radio frequency) techniques. small transceiver modules can be more uses for it are expected to be
built into a wide range of products, devised in the future. As the band
allowing fast and secure transmission becomes more widely used, radio
of data and/or voice within a given interference will increase. To counter
radius (usually 10 meters). Cables this interference, Bluetooth technolo-
may soon be a thing of the past-for gy incorporates several techniques to
the first time ever, personal area net- provide robust linkages. Among these
works can be created on an ad hoc or are cyclical redundancy encoding,
semi-permanent basis without cables packet re-transmission, and frequen-
or connectors and network adminis- cy hopping which can occur up to
tration problems. 1600 times per second.
Originally conceived as a cable capability from scratch, has the most suited to your type of device,
replacement, Bluetooth will obviously advantage of requiring fewer and to anticipate the kinds of issues
become much more as users continue resources, allowing shorter develop- you could encounter in integration.
to increase their reliance on informa- ment times and enabling faster time- By anticipating, investigating, and
tion transfer and connectivity. to-market. This option allows compa- understanding these issues, you'll be
Bluetooth is estimated to be installed nies to gradually develop competence in a much better position to integrate
in more than a billion devices by the in installing Bluetooth modules while Bluetooth modules into your devices
year 2005! And it seems it is here to also gaining experience in marketing with a minimum of time, engineering
stay. It is currently the fastest-grow- wireless products-or, alternatively, effort, and cost. However, with a fast-
ing standard in the electronics indus- to leverage the expertise of their changing technology such as
try. In short, Bluetooth technology is Bluetooth suppliers in enabling Bluetooth, no publication can cover
a key component of the wireless their products with a wireless link. every contingency, so guidance at this
future (Figure 1). point must be very general.
The purpose of this publication is to
Installing pre-built Bluetooth mod- guide you on how to analyze Bluetooth
ules, as opposed to creating wireless modules, to discern which one will be
Figure 1. Bluetooth will connect together a growing universe of wireless devices.
2
Table of Contents
Introduction 1 4. Pre-integration Factors 10
1. The Bluetooth Module 4 4.1 Power Supply and Battery 10
Battery Life 10
2. Type of Device 5 Power Consumption 10
Category 1: Adapters 5 Power Supply Noise 10
Category 2: Appliances 5 4.2 Radiated and Conducted
Category 3: Embedded Systems 5 Interference 10
Category 4: Mobile Phones 5 Step 1. Analysis with a Bluetooth
3. Module Specification Issues 6 Test Set 11
3. 1 Module Capabilities 6 Analysis in Normal Mode 11
Size 6 Analysis in Test Mode
(Transmit Mode) 12
Operating Temperature Range 6
Analysis in Test Mode
Operating Range 6 (Loopback Mode) 13
Profile/Maximum Data Throughput/ Important Note:
Packet Type 6 Link Establishment Problem 13
Sensitivity 6 Step 2. Analysis with a Bluetooth
Radio Performance 7 Test Set and Spectrum Analyzer 15
3.2 Physical and Electrical 4.3 Bluetooth Interference with "Host" 15
Characteristics of Module 7 4.4 Antenna Radiation Pattern 16
Physical Characteristics 7
Electrical Characteristics 7 Appendix A : Agilent Test
3.3 Module Test Tools 8
Equipment for Bluetooth
Technology 17
Test Access Points 8
Test Mode 8 Appendix B : References 19
3.4 Regulatory Approval 9 For More Information 20
3
1. The Bluetooth Module
A Bluetooth module consists primari- memory) which govern functionality Baseband Processor specification
ly of three functional blocks--a RF and interoperability with other mod- defines packet formats, physical and
transceiver unit, a baseband link ules. All Bluetooth modules have logical channels, plus the different
controller unit, and a support unit for these same functional blocks, but dif- modes of operation which support
link management and host controller ferent vendors' implementations will the transfer of voice and data
between devices. The Host Controller
interface (HCI) functions (Figure 2). have different attributes such as size
Interface (HCI) provides a common
Another functional component is of and degree of integration in silicon interface between the Bluetooth
course the antenna, which may be (e.g., single-chip solution vs. two or module and the host.
integrated on the PCB or come as a more chips).
standalone item. A fully implemented Bear in mind that all Bluetooth mod-
Bluetooth module also incorporates The RF Transceiver specification ules will need to pass the SIG qualifi-
defines the frequency bands, channel cation test, but this does not mean
higher-level software protocols
arrangement, and transceiver charac- that they will all have the same
(which can be resident in flash teristics of a Bluetooth system. The
characteristics.
Figure 2. Block diagram of a Bluetooth module, with two models shown.
4
2. Type of Device
The target application for your Category 4: Mobile Phones The following table (Table 1) provides
Bluetooth module will be your first an overview of some module specifi-
consideration. Quite simply, in what Bluetooth capability can be added to cation and pre-integration issues you
kind of device will you install your mobile phones in several ways--for should consider and analyze in
Bluetooth module? The usage model example, via battery packs, adapters, preparing for proper integration of a
of the device will largely determine or direct integration into the host. module into your device. The list is
not only the electrical and physical Hence this category can be a special not meant to be exhaustive. Please
environment in which the module is instance of Category 1 or Category 3 note that specifications can be pro-
placed, but the primary factors to but because of the expected market vided by the manufacturer, while
consider for integration as well. penetration, is treated as its own analysis of pre-integration factors
Among the growing classes of class. may require specific measurements
Bluetooth enabled devices are to be performed.
Having a full understanding of the
these:
device you plan to convert to wireless We will now look at these topics in
will make it easier to define the speci- more detail.
Category 1: Adapters fications of the Bluetooth module you
need, what performance factors you
PCMCIA card, compact Flash
should consider, and what kind of
Bluetooth card, USB Bluetooth
tests you may need to perform.
adapter, RS-232 Bluetooth dongle,
Bluetooth printer port converter,
etc. Such devices will allow you to
add a wireless link to your existing Table 1. Module Specification Issues and Pre-integration Factors
desktop PC, laptops, personal digital By Bluetooth Device Category
assistants (PDAs), printers, etc. with
Category 1 Category 2 Category 3 Category 4
Bluetooth technology.
Module Specification Issues-Information can be provided by your supplier.
Size N G N G
Category 2: Appliances
Operating Temperature Range G N G G
Wireless headsets which send and Operating Range N N N N
receive audio signals to and from Sensitivity G G G G
phones, cell phones, computer audio, Profile /Maximum Data Throughput /
MPEG players, home entertainment Packet Type G N G N
centers, etc., and computer peripher- Radio Performance G G G G
als such as keyboards, mice, joysticks, Physical & Electrical Characteristics N N N N
speakers and the like.
Test Mode N N N N
Test Access Points N N N N
Category 3: Embedded Systems Regulatory Approval N N N N
The device will normally be a comput- Pre-integration Factors-Analysis may require you to do specific measurements.
er or peripheral, but in this case the Battery life G G
Bluetooth module will be built direct- Power consumption N N N N
ly into the device without using the Power supply noise G N
interfaces of Category 1.
Radiated interference G G G G
This category can include desktops, Conducted interference G G G G
laptops, PDAs, or even printers, scan- BT interference with "host" N G
ners and fax machines. Obviously, it Radiation pattern G G G G
can overlap with Category 2 or 4. PCs G indicates that you should analyze this specification or pre-integration factor.
eventually will have Bluetooth cir- N indicates that you should think about it.
cuitry directly on the motherboard. indicates that you need not be concerned with it.
5
3. Module Specification Issues
Technical performance specifications Operating Range