• Document: RF Basics, RF for Non-RF Engineers
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RF Basics, RF for Non-RF Engineers Dag Grini Program Manager, Low Power Wireless Texas Instruments © 2006 Texas Instruments Inc, Slide 1 Agenda • Basics • Basic Building Blocks of an RF System • RF Parameters and RF Measurement Equipment • Support / getting started © 2006 Texas Instruments Inc, Slide 2 Definitions • dBm – relative to 1 mW • dBc – relative to carrier • 10mW = 10dBm, 0dBm = 1mW • -110dBm = 1E-11mW = 0.00001nW • For a 50 ohm load : -110dBm is 0.7uV, i.e. not much! • Rule of thumb: ƒ Double the power = 3 dB increase ƒ Half the power = 3 dB decrease © 2006 Texas Instruments Inc, Slide 3 dBm to Watt • About dBm and W ƒ Voltage Ratio aV = 20 log (P2/P1) [aV] = dB ƒ Power Ratio aP = 10 log (P2/P1) [aP] = dB ƒ Voltage Level V‘ = 20 log (V/1µV) [V‘] = dBµV ƒ Power Level P‘ = 10 log (P/1mW) [P‘] = dBm e.g. 25mW max. allowed radiated power in the EU SRD band >> P‘ = 10 log (25mW/1mW) = 10 * 1,39794 dBm >> 14 dBm © 2006 Texas Instruments Inc, Slide 4 Electromagnetic Spectrum SOUND RADIO LIGHT HARMFUL RADIATION VHF = VERY HIGH FREQUENCY 2.4 GHz 4G CELLULAR UHF = ULTRA HIGH FREQUENCY ISM band 56-100 GHz SHF = SUPER HIGH FREQUENCY ISM bands UWB EHF = EXTREMELY HIGH FREQUENCY 315-915 MHz 3.1-10.6 GHz ISM = Industrial, Scientific and Medical Source: JSC.MIL UWB = Ultra Wide Band © 2006 Texas Instruments Inc, Slide 5 Frequency Spectrum Allocation • Unlicensed ISM/SRD bands: • USA/Canada: ƒ 260 – 470 MHz (FCC Part 15.231; 15.205) ƒ 902 – 928 MHz (FCC Part 15.247; 15.249) ƒ 2400 – 2483.5 MHz (FCC Part 15.247; 15.249) • Europe: ƒ 433.050 – 434.790 MHz (ETSI EN 300 220) ƒ 863.0 – 870.0 MHz (ETSI EN 300 220) ƒ 2400 – 2483.5 MHz (ETSI EN 300 440 or ETSI EN 300 328) • Japan: ƒ 315 MHz (Ultra low power applications) ƒ 426-430, 449, 469 MHz (ARIB STD-T67) ƒ 2400 – 2483.5 MHz (ARIB STD-T66) ƒ 2471 – 2497 MHz (ARIB RCR STD-33) ƒ ISM = Industrial, Scientific and Medical ƒ SRD = Short Range Devices © 2006 Texas Instruments Inc, Slide 6 ISM/SRD License-Free Frequency Bands © 2006 Texas Instruments Inc, Slide 7 RF Communication Systems • Simplex RF System ƒ A radio technology that allows only one-way communication from a transmitter to a receiver ƒ Examples: FM radio, Pagers, TV, One-way AMR systems TX TX RX TX RX TRX TX TX © 2006 Texas Instruments Inc, Slide 8 RF Communication Systems • Half-duplex RF Systems ƒ Operation mode of a radio communication system in which each end can transmit and receive, but not simultaneously. ƒ Note: The communication is bidirectional over the same frequency, but unidirectional for the duration of a message. The devices need to be transceivers. Applies to most TDD and TDMA systems. ƒ Examples: Walkie-talkie, wireless keyboard mouse © 2006 Texas Instruments Inc, Slide 9 RF Communication Systems • Full-duplex RF Systems ƒ Radio systems in which each end can transmit and receive simultaneously ƒ Typically two frequencies are used to set up the communication channel. Each frequency is used solely for either transmitting or receiving. Applies to Frequency Division Duplex (FDD) systems. ƒ Example: Cellular phones, satellite communication © 2006 Texas Instruments Inc, Slide 10 Agenda • Basics • Basic Building Blocks of an RF System • RF Parameters and RF Measurement Equipment • Support / getting started © 2006 Texas Instruments Inc, Slide 11 Wireless Communication Systems

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