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AN9820.1 Dataheets PDF



Part Number AN9820.1
Manufacturers Intersil Corporation
Logo Intersil Corporation
Description A Condensed Review of Spread Spectrum Techniques for ISM Band Systems
Datasheet AN9820.1 DatasheetAN9820.1 Datasheet (PDF)

ee www.DataSheet4U.com TM A Condensed Review of Spread Spectrum Techniques for ISM Band Systems Application Note May 2000 AN9820.1 [ /Title in data transmission rate when compared with that for DQPSK, (AN98 Introduction and radios utilizing the MBOK modulation format have now The approval by the IEEE of the 20) achieved FCC certification. This application note provides an 802.11 Standard for wireless LANs has /Suboverview of several frequency hopping and direct sequence given the WLAN indust.

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ee www.DataSheet4U.com TM A Condensed Review of Spread Spectrum Techniques for ISM Band Systems Application Note May 2000 AN9820.1 [ /Title in data transmission rate when compared with that for DQPSK, (AN98 Introduction and radios utilizing the MBOK modulation format have now The approval by the IEEE of the 20) achieved FCC certification. This application note provides an 802.11 Standard for wireless LANs has /Suboverview of several frequency hopping and direct sequence given the WLAN industry a needed techniques used for wireless data transmission in the ISM ject (A boost. Manufacturers of WLAN band. Included is a discussion of how the MBOK modulation Consystems are now cooperating in performing interoperability technique is able to achieve Ethernet speeds over three densed testing. Such testing is providing assurance that 802.11 separate band-limited channels within the ISM band. compliant equipment purchased from one manufacturer will Revie interoperate with 802.11 radios manufactured by other OEMs. It will be shown that for a given increase in waveform w of This is an important consideration for MIS managers who complexity the MBOK modulation adds very little system Spread desire to use WLAN technology to provide mobility with complexity in terms of the number of components and radio Specconnectivity to their workforce. bill of materials (BOM) cost, when compared to a 2Mbit/s trum radio with QPSK modulation. The November 1997 approved 802.11 Standard defines the Techprotocol and compatible interconnection of data communication A Variable Data Rate Radio niques equipment via radio or infrared air interface in a local area Figure 2 depicts a system implementation of a 2.4GHz DSSS for network. The radio implementation of the PHY, a subject of this radio called PRISM™ designed for operation in the unlicensed paper, specifies the use of either Frequency-Hopping Spread ISM industrial, scientific and medical (ISM) band. By unlicensed Spectrum (FHSS) or Direct Sequence Spread Spectrum Band band, we mean that frequency band of 2400MHz to (DSSS) modulation. For frequency-hopping radios the IEEE Sys2483.5MHz allocated by the FCC wherein an intentional, specifies a minimum requirement of 1Mbit/s data rate using tems) m two-level Gaussian frequency shift keying (2GFSK) modulation. unintentional or incidental radiator may be operated without an t4U.co e /Autho individual license [1]. This international band is also defined by DataShee An optional rate of 2Mbit/s is supported using four-level regulatory agencies in Canada, Europe, and Japan although in r () Gaussian FSK (4GFSK) modulation. Figure 1 is a comparison DataSheet4U.com a few countries minor differences in allocated frequencies are of the signaling schemes for 802.11 2GFSK and 4GFSK. IEEE /Keyfound. Table 1 shows the operating frequency ranges in effect Std 802.11 specifies h2, the deviation factor, as 0.32 nominal words internationally for the 2.4GHz ISM band [2]. (Inter- for 2GFSK and h4 = 0.45 x h2 nominal for 4GFSK. TABLE 1. ISM BAND OPERATING FREQUENCIES For direct sequence systems two modulation formats and sil LOWER UPPER Corpo- data rates are supported, a basic access rate of 1Mbit/s CARRIER CARRIER and an enhanced access rate of 2Mbit/s. Both data rates ration, FREQUENCY FREQUENCY REGULATORY utilize phase shift keying modulation with differential binary LIMIT (GHz) LIMIT (GHz) RANGE GEOGRAPHY semiphase shift keying (DBPSK) used for the 1Mbit/s basic con2.402 2.480 2.400 to 2.4835 North America access rate and differential quadrature phase shift keying and Europe ductor, (DQPSK) used for the enhanced access rate. These two PRIS M, Wireless Communication s, RF, Radio Fre- techniques, FHSS and DSSS, constitute the currently approved standard for IEEE 802.11. Another modulation technique known as M-ary Biorthogonal Keying (MBOK) has been used to achieve a 5.5X improvement FREQUENCY 2GFSK 2.473 2.447 2.448 4GFSK 2.495 2.473 2.482 2.471 to 2.497 2.445 to 2.475 2.4465 to 2.4835 Japan Spain France CENTER FREQUENCY h2 h4/2 h4 SYMBOL TIME INTERNAL TIME DataSheet4U.com FIGURE 1. SIGNALING SCHEMES FOR 2GFSK AND 4GFSK MODULATION 1 1-888-INTERSIL or 321-724-7143 | Intersil and Design is a trademark of Intersil Corporation. | Copyright © Intersil Corporation. 2000 PRISM® is a registered trademark of Intersil Corporation. PRISM and design is a trademark of Intersil Corporation. DataSheet 4 U .com m et4U.co DataSheet4U.com DataSheet 4 U .com 2 www.DataSheet4U.com HFA3726 Q MODEM (FILE# 4310) HFA3424 (FILE# 4131) QUADRATURE DEMOD ADC I ADC CCA DESPREAD LNA Q ADC DEMODULATE Application Note 9820 HFA3624 RF/IF (FILE# 4066) DataSheet4U.com I/Q LO LOW-PASS FILTERS HFA3860B BASEBAND PROCESSOR TX/RCV DATA I/O HFA3841 MEDIA ACCESS CONTROLLER OR USER-SUPPLIED MAC RFPA SPREAD HFA3925 (FILE# 4132) POWER AMP AND SWITCH VCO VCO MODULATE/ ENCODE CONTROL TEST I/O QUAD IF MODULATOR OSC DUAL SYNTHESIZER HFA3524A FIGURE 2. 2.4GHz PROGRAMMAB.


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