Microwave Engineering Europe - October 2007 - (Page 25)

WIRELESS HID 25 SINCE 1973 Figure 1: Bluetooth protocol stack. In the area of immunity, Bluetooth uses FHSS (Frequency-Hopping Spread Spectrum) and splits the 2.4-GHz ISM band into 79 1-MHz channels. Bluetooth devices hop among the 79 channels 1600 times per second in a pseudo-random pattern. WirelessUSB uses a radio signal similar to Bluetooth but uses DSSS instead of FHSS. Each WirelessUSB channel is 1 MHz wide, allowing WirelessUSB to split the 2.4 GHz ISM band into 79 1-MHz channels like Bluetooth. WirelessUSB devices are frequency agile, using a “ﬁxed” channel, but dynamically change channels if the link quality of the original channel becomes suboptimal due to interference or other factors. This “ﬁxed” channel selection allows WirelessUSB to dynamically locate quiet areas of spectrum and productively use them. Since the developer can change both sides of the system to ﬁt his environment, this “ﬁxed” channel can be tailored to a speciﬁc application or environment. In the world of HID, there are few design issues more signiﬁcant than battery life. Consumers simply do not want to have to change batteries often. This feature is signiﬁcantly inﬂuenced by protocol implementation, data transfer times, and ﬁrmware optimization. For example, Bluetooth devices must synchronize with the network on a regular basis to “discover” new devices. In applications where devices regularly enter and leave the network, “discovery” is a required and vital function. In a low-cost multipointto-point system, servicing the protocol can sometimes be responsible for consuming more power than the data it transmits! If a device is designed to transmit data efﬁciently, it spends less time transitioning in and out of transmit and receive modes, spends less time on the air transmitting actual data, and ultimately does not suffer as signiﬁcantly on battery life. Choosing a proprietary system optimized for these characteristics can yield signiﬁcant improvement in power consumption. Wireless HID design is a unique market. Technologically, radio, baseband, and protocol development are sophisticated challenges. Power, security, and user-experience are also critically important. On top of it all, battery life and price reign paramount. So developing a sophisticated yet simple, advanced yet inexpensive system is a no small task. Developers are faced with a tough decision on choosing an open standard that provides established, widespread technology but handicaps a design with overhead and complexity, or choosing a proprietary solution optimized for speciﬁc applications with the risks of single-vendor solutions. Ultimately, designers may need to decide if they choose to lead or to follow, choose to be similar or different, choose to be safe or to be innovative. References Avoiding Interference in the 2.4-GHz ISM Band, EETimes CommsDesign Feb 2005: An efﬁcient 2.4-GHz wireless net for less, EETimes, October, 2003. Company Information YIG OSCILLATORS Omniyig Model No. YOM1517 YOM1518 YOM3597 YOM1949 YOM1988 YOM1515 YOM1516 YOM818 Freq. Range RF Pwr. Out. 2nd Har. (GHz) (mW) (dBc) 00.5 - 02.0 01.0 - 04.0 02.0 - 08.0 03.0 - 10.0 03.5 - 12.4 04.0 - 18.0 06.0 - 18.0 08.0 - 18.0 20 20 20 20 20 10 20 20 15 15 12 10 10 10 10 12 We offer other models w/ 2nd Harmonic –60 dBc and Oscillators integrated w/ 2-stage filters. YIG FILTERS Omniyig Model No. 4-STAGE S104 C104 X104 Ku104 6-STAGE C106 X106 Ku106 Freq. Range (GHz) Ins. Loss (dB) Bandwidth @ 3 dB (MHz) 02.0 - 04.0 04.0 - 08.0 08.0 - 12.4 12.4 - 18.0 04.0 - 08.0 08.0 - 12.4 12.4 - 18.0 4.0 4.0 4.0 4.0 4.5 4.5 4.5 6.5 6.5 6.5 6.5 20-35 25-40 25-40 28-45 25-40 25-40 28-45 25-40 25-40 30-60 25-60 Cypress Semiconductor www.cypress.com DUAL 4-STAGE C1044 04.0 - 08.0 X1044 08.0 - 12.4 Ku1044 12.4 - 18.0 M1044 02.0 - 18.0 Many other custom unit designs are available. Integratable with Analog or 12-bit TTL drivers. OMNIYIG INC. 3350 Scott Blvd., Bldg. #66, Santa Clara, CA 95054 Phone: (408) 988-0843 • Fax: (408) 727-1373 omniyig@ix.netcom.com • www.omniyig.com Figure 2: Minimum packet lengths for WirelessUSB and Bluetooth. 33 YEARS Microwave Engineering ● October 2007 ● www.mwee.com 024-025_MWEE.indd 25 20/09/07 13:05:02 http://www.cypress.com http://www.omniyig.com http://www.omniyig.com http://www.mwee.com

Table of Contents Feed for the Digital Edition of Microwave Engineering Europe - October 2007

Microwave Engineering Europe - October 2007 Contents Comment News CMOS RF: Si-On-Sapphire Goes Mainstream Cover Feature: New Data Protection Concept for UHF RFID Tags CMOS RF: RF Design Team Touts CMOS Spin for 3G PAs Wireless HID – Are You Following the Standard to Another “Average” Product Development? Phase Optimisation of the RF Front-End Direct Synthesis of UWB-WiMedia Signal Generation 4G Chips to Target 700 MHz Applications Femtocells Mobilize to Fight Wi-Fi in the Home Products Product Feature: AXIEM Pioneers the Future of EM Technology Calendar

Microwave Engineering Europe - October 2007

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