Conexant Systems 36342U Spread Spectrum Transmitter User Manual AN9949

Conexant Systems Inc. Spread Spectrum Transmitter AN9949

Manual

INCHECKING

AN9949

ISL36342U-EVAL PRISM II 11Mbps USB Wireless

LAN Evaluation Kit User’s Guide

Introduction

This kit allows evaluation of the

Intersil PRISM® II Direct Sequence

chip set design in a Wireless Local

Area Network (WLAN) USB Card implementation.

Software drivers are included allowing data to be transmitted

between cards at 1, 2, 5.5 and 11Mbps transfer rates, with a

diagnostic program to display the real data throughput from

system to system.

Included in the kit are PRISM II chip set data sheets with

application notes describing the implementation of a

wireless networking card using the chip set.

Contents of Your Evaluation Kit

Your PC Card Wireless LAN Evaluation Kit contains the

following items:

Should you discover that your PC Card Wireless LAN

Evaluation Kit is incomplete, please contact Intersil

Corporation.

Overview of IEEE 802.11

The IEEE 802.11 specification is a standard for wireless

connectivity for fixed, portable, and moving stations within a

local area.

The IEEE 802.11 standard describes the services required

by a compliant device to operate within an “ad hoc” or

“infrastructure” network, as well as dealing with the issues

related to mobility within those networks. Spread spectrum

techniques are used to tolerate mobility and multipath

effects. They are also a requirement for compliance with

FCC, ETSI and those of other regulatory authorities when

operating within the Industrial, Scientific, and Medical (ISM)

frequency band.

An ad hoc communications network is created quickly and

informally for a temporary time period. An infrastructure

network usually requires more planning so that wireless

stations can communicate over longer distances through

access points, and may also communicate with existing

wired LANs using portals.

The IEEE 802.11 standard describes Media Access Control

(MAC) procedures. The principal method of communication

is the Carrier Sense Multiple Access with Collision

Avoidance (CSMA-CA) protocol. Using this protocol, each

station senses the communications medium (RF channel),

and does not transmit until the channel is clear. This avoids

collisions and minimizes the retransmission of subsequent

packets.

The standard also supports the operation of a station within

a wireless LAN that may coexist with several overlapping

wireless LANs. To accomplish this, a scheme of

channelization and spread spectrum techniques is used.

Direct Sequence (DSSS) and Frequency Hopping (FHSS)

spread spectrum techniques are supported by the standard

and both operate in the 2.4GHz to 2.4835GHz frequency

band (the unlicensed ISM band). An infrared technique is

also supported for indoor applications. The standard

supports a 1Mbps and 2Mbps data rate for both DSSS and

FHSS and has recently introduced a high data rate standard

supporting 5.5Mbps and 11Mbps DSSS using

Complementary Code Keying (CCK) modulation.

The standard has also specified the requirements and services

that enable private and secure communications to occur.

Wireless LAN Configurations

For ease of use in evaluating these cards, an ad hoc

network for peer to peer communications can be created.

An ad hoc network is usually created for a specific purpose

(such as file transfer or accessing a database). Ad hoc

networks simplify the process of creating and dissolving

networks for nontechnical users of the network facilities.

Two cards form an IEEE 802.11 Independent Basic Service

Set (IBSS), the simplest ad hoc network. The cards

communicate with each other directly and must remain

within radio range. When both cards are on, they

immediately “see” each other and the ad hoc network is

formed without user intervention.

TousethecardsinaninfrastructureBSS(alsocalledan

Extended Service Set) where the two cards may not be in direct

radio contact, access points are needed. The association

between a card (station) and an infrastructure BSS - where

communication occurs only between a station and an access

point and not between stations directly is dynamic.

QUANTITY DESCRIPTION

2 PRISMIIWirelessLANPCCards

1 ISL36342U Wireless LAN Evaluation Kit User’s

Guide, AN9949

1 PRISM II Chip Set Data Sheets

1 PRISM II Application Notes

1 Microsoft® Windows® 98, 98SE, MS, Win2000

Drivers

1 PRISM® Test Utilities (PTU) Software

1 Features/Benefits Card

1 Product Registration Form

1 Notification Card

Application Note June 2001

Author: Richard L. Abrahams

1-888-INTERSIL or 321-724-7143 |Intersil and Design is a trademark of Intersil Americas Inc.

PRISM® is a registered trademark of Intersil Americas Inc. PRISM and design is a trademark of Intersil Americas Inc.

Microsoft® Windows® and Windows NT® are registered trademarks of Microsoft Corporation. LINUX® is a registered trademark of Linus Torvalds.

The IEEE 802.11 protocols are implemented in the firmware

so that file transfers or database access can begin

immediately.

Direct Sequence Spread Spectrum Approach

The use of spread spectrum techniques for wireless

computer communications is widely accepted because of

its robustness against multipath effects and interference

from intentional or unintentional radiators. The use of

spread spectrum techniques in the ISM frequency band

also allows products to be deployed without the need for an

FCC license.

The two main methods by which spread spectrum

communications can be achieved are Direct Sequence

Spread Spectrum (DSSS) and Frequency Hopping Spread

Spectrum (FHSS). This wireless LAN PC card uses the

DSSS technique. DSSS transmission has the best

performance in terms of multipath immunity and jamming

rejection. In an office environment, jamming sources are

likely to be unintentional such as emissions from

microwave ovens. Even though unintentional, they pose a

threat to the communications network. Direct sequence

techniques are superior to frequency hopping systems in

this case because FHSS gains its immunity to jamming by

avoiding the location of a single tone jammer (such as

other FHSS users). When collisions occur, data is lost. With

a DSSS system, the despreading function in the receiver

gives immunity to jamming by spreading the interfering

energy by the Pseudo Random Number (PN) code over the

whole bandwidth. This selective despreading attenuates

the jamming power while despreading the desired signal.

In the office environment, multipath effects may degrade

network communications. Direct sequence techniques offer

better protection than slower frequency hopping systems in

the presence of multipath interference. With frequency

hopped systems, if the hopper jumps to a frequency where a

null resides, then data is lost until the next hop. Multipath

signals can be thought of as a special case of unintentional

jamming. In the DSSS approach, nulls resulting from

multipath fading only eliminate a fraction of the signal power

since the bandwidth in the DSSS case is very large. A

significant amount of energy still remains in the signal and

effective despreading still occurs. The probability of burst

errors is reduced significantly.

An often overlooked factor when comparing IEEE 802.11

compliant DSSS and FSSS implementations, is the

achievable data rate. A frequency hopping occupied

bandwidth of 1MHz as specified by the FCC acts as a

limitation when using data rates beyond 2Mbps. A similar

bandwidth limitation has not been imposed when using the

direct sequence implementation. In the new 802.11 high data

rate (11Mbps) standard utilizing Complementary Code

Keying (CCK) modulation, the 5-1/2 times increase in data

rate has been achieved in the same 17MHz bandwidth! This

is accomplished by encoding 6 bits of data in one out of a

possible 64 orthogonal PN spreading sequences. More

information on the new high data rate standard may be

found in Applications Note AN9850 “Complementary Code

Keying Made Simple” which may be found on the Intersil

Web Site.

Installation of ISL36342U Windows

Drivers

PRISM Test Utility (PTU) Software

Installation

NOTE: Perform after Windows Driver Installation.

Step 1. Boot your PC under Microsoft Windows.

Step 2. Once your system has booted and is idle, insert

PRISM II Driver for Windows, Disk #1 into the “A”

Floppy Drive. On the Desktop, left click on

<Start>-><RUN> then type A:SETUP <Enter>

Follow the on-screen instructions. Accept all defaults.

Step 3. When the preliminary installation is complete,

connect the wireless LAN PC card to the computer

via the USB cable.

Step 4. Windows should automatically recognize that the

card has been inserted. It then displays a dialog box

titled “New Hardware Found”.

Step 5. Insert PRISM II Driver for Windows, Disk #1 into

the floppy drive. Tell Windows that the driver is

located on drive “A”. Accept all defaults.

Step 6. Follow the on-screen instructions to complete

installation of the driver. When complete, the NDC

driver icon should appear in the system area on the

desktop (computer monitor with antenna). Clicking on

this icon enables setting of channel, mode, etc.

Step 7. If operating in the Pseudo IBSS mode, you must

assign a unique IP address to the computer in

order for the card to be operable. Left click on

<Start>-><Settings>-><Control Panel>.

Double click on Network. Select TCP/IP ... PRISM

IEEE 802.11 PC Card .... and click on Properties.

Select the IP Address tab. Click on Obtain an IP

Address. Enter a valid IP address. Enter a valid

Subnet Mask (suggest 255 255 255 0). Click

on OK.

Step 1. Insert the PTU disk #1 into the floppy drive.

Step 2. On the Desktop, left click on <Start>-><RUN>

then type A:setup <Enter>. Follow the on-screen

instructions. Accept all defaults. When the

installation is complete, an icon should

automatically appear on the Desktop.

Application Note 9949

PC Card Evaluation

This chapter describes several software programs supplied

with the kit. It also details some diagnostic test points that

may be accessed on the card.

Using the PRISM Test Utility (PTU) Software

The PTU permits continuous operation of the transmitter. It is

therefore convenient for performing RF measurements such

as Transmitter Power. It also provides a handy method of

changing channels within the ISM band, Use of the PRISM

Transmitter Test Utility is basically self explanatory. An icon

was automatically created on the desktop when the PTU

installation was performed. It may be run by double-clicking

on this icon.

Using the LANEVAL Software

LANEVAL provides a convenient method of analyzing

Packet Error Rate (PER) and Receiver Sensitivity. An icon

for starting LANEVAL was automatically placed on the

desktop when the PTU installation was performed. In order

for LANEVAL to form a successful link, the same packet

parameters (e.g., Packet Length, Packet Pad Words, etc.)

most be programmed at each end of the link.

LANEVAL runs in conjunction with the NDC Driver. The

Driver permits selection of Data Rate and Channel. It is

normally run in the Pseudo IBSS mode as this provides a

simple wireless Ad Hoc link between two computers. The

NDC Driver may be easily accessed by double-clicking on its

icon (looks like a computer with an antenna on top) located

in the System Tray area on the desktop.

List of Test Instruments

The following instruments may be used for conducting tests

on the wireless LAN PC card.

INSTRUMENT MANUFACTURER MODEL

Spectrum Analyzer Hewlett-Packard 8595E

Power Meter Giga-tronics 8541B

Signal Generator Hewlett-Packard 8648C

Frequency Counter Hewlett-Packard 53181A (012 Option)

Digital Scope

General-Purpose Multimeter

Computer with a USB Connection Slot (2 Required)

Differential Probe Tektronix P6247

RF Probe, 500ΩHewlett-Packard 54006A + 11742A

Application Note 9949

FIGURE 1. WIRELESS LAN PC CARD BLOCK DIAGRAM

HFA3863 BBP

AGC

CTL

RAKE

ALC

AND

DEMOD

DAC

ADC

DAC

I ADC

Q ADC

DAC

ADC

I DAC

Q DAC

MOD

I/O

AND

FILTER

IF LO

I/Q LO

PLL

HFA3783 (FILE #4633)

IF I/Q MOD/DEMOD

RF LO

PLL

HFA3683A

RF/IF CONVERTER

HFA3983

REF_OUT

CONTROL

TEST I/O

HFA3842 MAC

(FILE #4839)

USB

INTERFACE

MEMORY

ACCESS

ARBITER

USB

INTERFACE

LOGIC

RADIO

DATA

INTERFACE

RADIO

CONTROL

PORTS

SERIAL

PORTS

WEP

ENGINE

CPU

16-BIT

PIPELINED

CONTROL

PROCESSOR

EXTERNAL

MEMORY

(FILE #4635)

(FILE #4634)

(FILE #4868.1)

VCO

OSC

BUFFER

VCTRL

44MHz

OSC

48MHz

Application Note 9949

Test Point Diagrams

FIGURE 2. WIRELESS LAN PC CARD TEST POINTS (TOP VIEW)

ISL36342U-EVAL

S/N

REV B

INTERSIL CORP0RATION

ISL36342U-EVAL REV B

PRISMII RADIO USBUS

DATE:23/OCT/00

C150

TP12

L29

R74

R82

R24

C27

L21

C144

R14

TP13

U18

R15 C24

R83

C33

R96

C10

C143

C13

R20

R28

C25

C26

C15

R34

R30

C30

C32

R16

R12

R22

C17

C21

R32

R33

C36

C19

R42

C20

R18

R13

C34

C139

C29

C35

TP11

C14

TP15

TP14

R94

C31

C18

C140

R29

R27

R23

R19

C12

C11

R90

C152

C147

R72

R95

C148

R93

R92

R91

C146

C145

TP5

TP8

L26

TP10

C138

TP4

C122

L28

C64

C119

TP2

R85

L25

TP9

TP7

TP6

C131

L24

L27

TP3

TP1

C149

ASSEMBLY TOP

USB Attached

USB D-

USB D+

48 MHz

TEST POINT K- RX I+ SIGNAL

TEST POINT L - RX Q+ SIGNAL

TEST POINT L1 - RX Q- SIGNAL

TEST POINT K1 - RX I- SIGNAL

vReg +3.3V

Application Note 9949

FIGURE 3. WIRELESS LAN PC CARD TEST POINTS (BOTTOM VIEW)

Test Point Diagrams (Continued)

C37

L15

C77

R46

FL3

U10

C28

C96

C97

C141

C151

C65

C48

L11

C66 R43

C82

C105

R53

FL4

C73

U8 L13

C79

C98

L16

L19

L20

C106

C101

L18

U12

C127

R71

U12

C90

R50

R48

C54

C113

R60

R54

R68

C128

C126

C22

C68

C59

C95

C83

C87 R51

C16

C111

C115

C114

C94

R35

FL5

R31

C58

C60

C61

R38

R37

R36

R73

U11

C117

C67

C78

C118

C123

C116 R65

C23

R25

C109

C129

C125

R69

C44

C39

C62

C49

C47

R39

C63

R81

R80

L12

C92

C86

R44

L14

U11

U14

R75

C132

R77

R76

C130

FL1

C74

C75

C103

C99

R84

U16

C50

C135

C69

C46

C45

C72

C53

C76

C84

C89

C91

C80

C124

C100

R55

R52

C107

R56

C136

U15

C137

C38

C40

C42

L10

C55

C51

C52

C56

R40

C112

R63

C108

C104

C110

C120

U13

R70

R66 C134

C133

C43

C41

C71

C57

C70

R45

C93

C81 L17

R49

R47

C88

C85

R64

R61

R57

R58

R59

R62

C121

R67

C102

L22

C142

U17

INSTALL FOR RF CONNECTOR

TEST POINT D - TX IF SIGNAL (AFTER SAW FL)

REMOVE FOR RF CONNECTOR

C141 (150 PF)

L4 (1.5 NH)

INSTALL FOR RF CONNECTOR

C137 (150 PF)

ALSO INSTALL C141 (SEE BELOW)

ALSO INSTALL C137 (SEE ABOVE)

RF IN/OUT

TEST POINT E

(INSTALL J1 FOR

)

RF CONNECTOR)

J- RX IF+ SIGNAL

TEST POINT

TEST POINT C

TX IF SIGNAL (BEFORE SAW FL)

TEST POINT F - RF L.O.

TEST POINT G

RF L.O. LOCK VOLTAGE

TEST POINT A

TX I+

TEST POINT A1

TX I-

TEST POINT B

TX Q+

TEST POINT B1

TX Q-

TEST POINT I IF L.O. LOCK VOLTAGE

TEST POINT H IF L.O.

Application Note 9949

Receiver Noise/Gain Analysis

The ISL36342U is implemented on FR-4 material. It uses 50Ω

coplanar micro-strip traces which have a loss of 0.35dB/in at

2.442GHz. These losses are small, but should be considered

when calculating the overall noise figure. The ISL36342U uses

two diversity antennas. The first component is the antenna

diversity select switch. This has an insertion loss of 1dB. The

input trace to the switch along with the matching network

associated with the switch brings the insertion loss to 2dB. The

next component is a low pass filter. This filter provides transmit

harmonic suppression. Its insertion loss is 1dB including the

trace loss and matching loss from T/R switch. The next

component is a bandpass filter. This filter limits the front end

pass band to the ISM band, and provides out-of-band rejection

for all undesired signals (e.g., cell phones). The filter

characteristic is shown is Figure X. The insertion loss from this

filter is 2.5dB including the effect of trace length. The bandpass

filter is followed by a Transmit/Receive (T/R) switch. This switch

connects the LNA or the Power Amplifier (PA) to the antennas.

The insertion loss from this switch is 2.5dB including the effects

of trace lengths and matching components. The LNA is the next

component in the receive path. The LNA is inside the

HFA3683A RF/IF converter and synthesizer, which also

contains a image reject mixer, as well as the frequency

synthesizer for the first Local Oscillator (LO). The first LO is low

side injected to mix the desired channel to the Intermediate

Frequency (IF) of 374MHz. The first LO tunes in 5MHz steps

and is 374MHz below the ISM band channels. The first LO tune

from 2038MHz to 2110MHz. The cascaded noise figure and

gain of the LNA and the image reject mixer in the high gain

mode is 3.7dB and 25dB respectively. The IF filter is a Surface

Acoustic Wave (SAW) filter. The passband of the SAW filter is

±10MHz which provides adjacent channel rejection. It has

linear phase, sharp attenuation characteristics and provides

50dB of ultimate suppression. The final component is the

HFA3783 I/Q modulator/demodulator and synthesizer. The

HFA3783 contains AGG amplifiers and a quadrature baseband

converter. The HFA3783’s maximum gain is 61dB while the

worst case noise figure is 8dB. The HFA3783 provides complex

I and Q filtered inputs to the base-band processor. A spread

sheet showing the noise gain analysis is shown in Figure X. In

the low gain, mode the LNA gain is switched via the AGC to

-9dB of loss. The noise gain cascade for the low gain mode is

shown in Figure X.

HFA 3683A

HFA 3783

Bandpass Filter

USN 30172450

2dB IL

T/R Switch

UPG-152TA

1dB IL

OCP 27

OIP3 50

Diversity

Switch

UPG-152TA

1dB IL

OCP 27

OIP3 50

Lowpass Filter

LTF3216L

1dB IL

LNA/Image

Rejection Mixer

Gain 25 dB

NF 3.7dB

OCP -7.5

OIP3 12

374MHz

Saw Filter

8.5dB IL

HFA 3783

Gain 61

NF 7dB

OCP -14.3

OIP3 1.5

FIGURE 4.

FIGURE 5. INPUT FILTER

FIGURE 6. SAW FILTER

Application Note 9949

Explanation of Test Points

All measurements were taken using the “Continuous

Transmit” or “Continuous Receive” features of the PTU

diagnostic software. Unless otherwise noted, spectrum

measurements included in this section were obtained using

a Hewlett-Packard 54006A 500Ωprobe and 11742A coaxial

blocking capacitor and do not indicate the actual amplitude

of the signal owing to losses associated with the probe.

Unless noted, 11Mbps CCK modulation was employed.

Many of the signals are differential (i.e., balanced with

respect to ground). These are denoted by + (plus) and

- (minus) symbols following the signal name (e.g., RX I+ and

RX I-).

Test Points A- A1, and B-B1

Transmit I and Q:

NOTE: BPSK mode is used for the plots in this figure. Therefore, I

and Q are identical.

TABLE 1. HIGH GAIN PARAMETERS

PART

REFERENCE NF GAIN OCP OIP3 CUM NF CUM GAIN ICP OIP3 IIP3

UPG152TA2 -227502.00-22950.0052.00

LTF3216L 1 -1 99 99 3.00 -3 29 49.00 52.00

LFSN30172450 2 -2 99 99 5.00 -5 29 47.00 52.00

UPG152TA2 -227507.00-72943.8150.81

HFA3683A 3.7 25 -7.5 12 10.70 18 -25.5 12.00 -6.00

SAW374M 8.5 -8.5 99 99 10.74 9.5 -25.5 3.50 -6.00

HFA3783 7 61 -14.3 1.5 10.90 70.5 -84.8 1.50 -69.00

TABLE 2. LOW GAIN PARAMETERS

PART

REFERENCE NF GAIN OCP OIP3 CUM NF CUM GAIN ICP OIP3 IIP3

UPG152TA 2 -2 27 50 2.00 -2 29 50.00 52.00

LTF3216L 1 -1 99 99 3.00 -3 29 49.00 52.00

LFSN30172450 2 -2 99 99 5.00 -5 29 47.00 52.00

UPG152TA 2 -2 27 50 7.00 -7 29 43.81 50.81

HFA3683A 3.7 -9 -7.5 12 10.70 -16 8.5 11.98 27.98

SAW374M 8.5 -8.5 99 99 24.04 -24.5 8.5 3.48 27.98

HFA3783 7 -72 -14.3 1.5 31.41 -96.5 8.5 -68.52 27.98

FIGURE 7. TRANSMIT I AND Q SIGNALS AT THE OUTPUT

OF THE HFA3861 (TEST POINTS A-A1 AND B-B1)

Application Note 9949

The I and Q are both differential signals and, as such,

consist of I+, I-, Q+, and Q- respectively. As these are

balanced signals, data is measured using a Tektronix P6247

Differential Probe. For example in the measurement of the I

signal, the probe is bridged between Test Points A (I+) and

A1 (I-).

Transmit In-phase and Quadrature (I+ and Q+) signals are

the spread baseband single-bit I and Q digital data that are

outputted at the programmed chip rate (N).

Test Points C and D

IF Transmit Signal:

The intermediate frequency (IF) transmit signal is a spread

spectrum signal centered at 374MHz with a 17MHz

bandwidth.

The SAW filter is used to shape the sidelobes.

Test point C is at the input of the SAW Filter whereas D is at

the output.

Test Point E

RF Transmit Signal:

The optional SMA connector can be used to hook up a

Spectrum Analyzer for RF evaluation. Note that L4 (1.5nH)

must be removed and C141 (15pF) and C37 (150pF) must

be installed to activate the connector See (Figure 3).

This is the up-converted spread spectrum output of the card.

The center frequency of this signal is 2412-2484MHz

depending on the channel of operation. The output power of

the signal is approximately +12.5dBm. The peaks of the

sidelobes of the output spectrum (i.e., the regrowth) are

normally adjusted by the ALC/AGC to be 30dB below the

peak of the spectrum per requirements of IEEE 802.11.

The following table delineates the IEEE 802.11 channels and

their corresponding center frequencies. Although information

contained in Table 1 is deemed to be accurate, local regulatory

authorities should be consulted before using such equipment.

FIGURE 8. IF TRANSMIT SIGNAL BEFORE SAW FILTER

(TEST POINT C)

FIGURE 9. IF TRANSMIT SIGNAL AFTER THE SAW FILTER

(TEST POINT D)

TABLE 3. IEEE 802.11 CHANNELS

CHANNEL

NUMBER CHANNEL

FREQUENCY GEOGRAPHIC

USAGE

1 2412MHz US, CA, ETSI, MKK

2 2417MHz US, CA, ETSI, MKK

3 2422MHz US, CA, ETSI, MKK

4 2427MHz US, CA, ETSI, MKK

5 2432MHz US, CA, ETSI, MKK

6 2437MHz US, CA, ETSI, MKK

7 2442MHz US, CA, ETSI, MKK

8 2447MHz US, CA, ETSI, MKK

9 2452MHz US, CA, ETSI, MKK

10 2457MHz US, CA, ETSI, FR, SP, MKK

11 2462MHz US, CA, ETSI, FR, SP, MKK

12 2467MHz ETSI, FR, MKK

13 2472MHz ETSI, FR, MKK

14 2484MHz Japan†

KEY: US = United States, CA = Canada, ETSI = ETSI countries

(except France and Spain), FR = France, SP = Spain.

†In Japan, Channel 14 requires Japanese Transmit Filter.

FIGURE 10. TRANSMITTED 2.4GHz SIGNAL SPECTRUM

(TEST POINT E)

Application Note 9949

Test Points F and G

RF local oscillator (LO):

The behavior of the RF VCO can be monitored at Test Point F.

The VCO output should be locked at the channel frequency

minus the IF (374MHz.) This means that the VCO will have

to lock between 2038MHz and 2110MHz. The output power

at test point F is approximately -6dBm. Ideally, the tuning

voltage of the VCO, when locked, falls between 0.5V and

2.2V. The tuning voltage of the RF VCO can be observed at

Tes t Point G.

Test Points H and I

IF local oscillator (LO):

The IF VCO is a discrete design and operates at 748MHz

(i.e., twice the IF frequency). The output frequency of this

VCO does not need to be varied; thus, minimal tuning range

is required.

The output frequency of this VCO can be observed at Test

Point H.

Ideally, the tuning voltage of the IF VCO, when locked, falls

between 0.5V and 2.2V. The tuning voltage of the IF VCO

can be observed at Test Point I.

Test Point J

IF Receive Signal:

The intermediate frequency (IF) receive signal is the down-

converted receive signal prior to the SAW bandpass filter.

The center frequency of this signal is 374MHz with a

bandwidth of 17MHz. The power of this signal is directly

dependent on the input signal power.

Note that the spurious signal visible below the DS

spectrum’s frequency is a harmonic of the 44MHz clock.

Much of this level is due to stray pickup in the 500ΩRF

probe because of the relatively low signal level present. As

such, it will have no influence on receiver performance.

Test Point K-K1 and L-L1

Receive I and Q:

NOTE: BPSK mode is used for the plots in this figure; as such, I and

Qareinverseofeachother.

FIGURE 11. RF LOCAL OSCILLATOR OUTPUT AT CHANNEL 8

(TEST POINT F)

FIGURE 12. IF LOCAL OSCILLATOR OUTPUT (TEST POINT H)

FIGURE 13. IF RECEIVE SIGNAL PRIOR TO SAW FILTER

(TEST POINT J)

FIGURE 14. RECEIVE I AND Q SIGNALS (TEST POINTS K AND L)

Application Note 9949

The receive In-phase and Quadrature (I and Q) signals are

the demodulated lowpass-filtered data that are coupled to

the HFA3861. The output levels of these two signals are

approximately 500mVP-P. As these are balanced signals,

data is taken using a Tektronix P6247 Differential Probe.

• Test point K for RXI+ signal is at the 0Ωjumper, R19.

• Test point K1 for RXI- signal is at the 0Ωjumper, R23

• Test point L for RXQ+ signal is at the 0Ωjumper, R27

• Test point L1 for RXQ- signal is at the 0Ωjumper, R29.

Operational Characteristics

See the iSL36342U-EVAL data sheet, Intersil File Number

FN8018, for more detailed specifications.

References

For Intersil documents available on the internet, see web site

www.intersil.com

[1] iSL36342U-EVAL Data Sheet, Intersil Corporation.

[2] AN9850 Application Note, Intersil Corporation,

“Complementary Code Keying Made Simple”.

Notices

Electronic Emission Notices

This device complies with Part 15 of the FCC rules.

Operation is subject to the following two conditions:

1. This device may not cause harmful interference.

2. This device must accept any interference received,

including interference that may cause undesired

operation.

FCC Radio Frequency Interference Statement

The wireless LAN PC card is subject to the rules of the

Federal Communications Commission (FCC). This card is

considered an intentional radiator as per the FCC guidelines.

NOTE: This equipment has been tested and found to comply with

the limits for a Class B digital device, pursuant to Part 15 of the FCC

rules. These limits are designed to provide reasonable protection

against harmful interference in a residential installation. This

equipment generates, uses and can radiate radio frequency energy

and, if not installed and used in accordance with the instruction

manual, may cause harmful interference to radio communications.

However, there is no guarantee that interference will not occur in a

particular installation. If this equipment does cause harmful

Absolute Maximum Ratings

SupplyVoltage..........................-0.3Vto7.0V(Max)

StorageTemperature(Note1).................. -20

oCto65

Operating Conditions

TemperatureRange........................ 0

oC≤ TA≤55oC

SupplyVoltageRange.......................... 4.20Vto7V

Caution: These are the absolute maximum ratings for the PC Card product.

Exceeding these limits could cause permanent damage to the card.

NOTE:

1. All temperature references refer to ambient conditions.

TABLE 4. GENERAL SPECIFICATIONS

SPECIFICATION VALUE

Targeted Standard IEEE 802.11

Data Rate 1Mbps DBPSK

2Mbps DQPSK

5.5Mbps CCK

11Mbps CCK

Range (11Mbps Data Rate) 120ft (37M) Indoor (Typ)

400ft (122M) Outdoor (Typ)

Center Frequency Range 2412MHz - 2484MHz

Step Size 1MHz

IF Frequency 374MHz

1.875"

FIGURE 15. EDGE VIEW, USB CARD

IF Bandwidth 17MHz

RX/TX Switching Speed 2µs(Typ)

Average Current without

Power Save

2% Transmit, 98% Receive

187mA (Typ)

Average Current with Power

Save

2% TX, 8% RX, 90% Standby

43mA (Typ)

Current in Continuous TX

mode

300mA (Typ)

Current in Continuous RX

Mode

185mA (Typ)

Standby Current 25mA (Typ)

Mechanical PC Card, with Antenna Extension

Output Power +11.5dBm (Typ)

Transmit Spectral Mask -30dBc at First Side Lobes

Antenna Interface SMA, 50Ω (for Testing Only)

Dual Diversity Printed Antenna

TABLE 4. GENERAL SPECIFICATIONS

SPECIFICATION VALUE

Application Note 9949

All Intersil products are manufactured, assembled and tested utilizing ISO9000 quality systems.

Intersil Corporation’s quality certifications can be viewed at website www.intersil.com/design/quality

Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design and/or specifications at any time without notice.

Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. How-

ever, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No

license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.

For information regarding Intersil Corporation and its products, see web site www.intersil.com

interference to radio ortelevision reception, which can be determined

by turning the equipment off and on, the user is encouraged to try to

correct the interference by one or more of the following measures:

• Reorient or relocate the receiving antenna

• Increase the separation between the equipment and the

receiver

• Connect the equipment into an outlet on a circuit different

from that to which the receiver is connected

• Consult the dealer or an experienced ratio/TV technician for

help

WARNING! Any changes or modifications of equipment not

expressly approved by Intersil could void the user’s authority to

operate the equipment.

Packaging

Application Note 9949

Conexant Systems 36342U Spread Spectrum Transmitter User Manual AN9949

Conexant Systems Inc. Spread Spectrum Transmitter AN9949

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