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| {{mergeinto|Frequency-shift keying|date=December 2011}}
| | Nice to meet you, I am Marvella Shryock. Body developing is 1 of the things I love most. Hiring has been my profession for some time but I've currently applied for another 1. Minnesota has usually been his house but his spouse desires them to move.<br><br>My web blog ... [https://mostlymusiccom.zendesk.com/entries/53427870-Prevent-Candida-Albicans-Before-Hand-With-These-Tips home std test kit] |
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| '''Gaussian Frequency-Shift Keying''' ('''GFSK''') is a type of [[Frequency Shift Keying]] [[modulation]] that uses a [[Gaussian filter]] to smooth positive/negative frequency deviations, which represent a binary 1 or 0. It is used by [[DECT]], [[Bluetooth]],<ref>Sweeney, D. "An introduction to bluetooth a standard for short range wireless networking" ''Proceedings. 15th Annual IEEE International ASIC/SOC Conference, Rochester, NY, USA, 25-28 Sept. 2002'', pp. 474–475. 2002. http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1158106</ref> [[Cypress WirelessUSB]], [[Nordic Semiconductor]],<ref>Nordic Semiconductor. [http://www.nordicsemi.com/files/Product/data_sheet/Preliminary_Product_Specification_nRF24LU1P_v1_2.pdf nRF24LU1+ Preliminary Product Specification v1.2]</ref> [[Texas Instruments LPRF]], [[z-wave]] and [[Wavenis]] devices. For basic data rate [[Bluetooth]] the minimum deviation is 115 kHz.
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| ==Generalization==
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| A GFSK modulator, is similar to a [[Frequency-shift keying|FSK]] modulator, except that before the [[baseband]] pulses (−1, +1) go into the FSK modulator, it is passed through a [[gaussian filter]] to make the pulse smoother so to limit its spectral width. Gaussian filtering is one of the very standard ways for reducing the spectral width, it is called "[[pulse shaping]]".
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| If we use −1 for <math>f_c - f_d</math> and +1 for <math>f_c + f_d</math>, once when we jump from −1 to +1 or +1 to −1, the modulated waveform changes rapidly, which introduces large out-of-band spectrum. If we change the pulse going from −1 to +1 as −1, −.98, −.93 ..... +.96, +.99, +1, and we use this smoother pulse to modulate the carrier, the out-of-band spectrum will be reduced.<ref>[http://www.palowireless.com/infotooth/knowbase/radio/109.asp www.palowireless.com "GFSK Differences & Advantages over FSK Modulation"]</ref>
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| ==References==
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| {{Reflist}}
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| [[Category:Quantized radio modulation modes]]
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Latest revision as of 07:32, 3 October 2014
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