7th entry

Assalamualaikum,

I am so busy this week :( however this blob need to go on. In this week we continue our lesson about bluetooth and another wireless technology. So here they are.....

BLUETOOTH

• concept: focus on point to point and point to multiple with small network called piconets
• when multiple network exist within the same room they become known as scatternet
• each piconet hold up 8 active unit

Piconets with a single slave operation (a), a multi-slave operation (b),

and a scatternet operation (c).

Piconets with a single slave operation (a), a multi-slave operation (b),

and a scatternet operation (c).

DEFINITION

Bluetooth is a wireless technology that is composed of hardware, software and interoperability requirement. Bluetooth is specification for short-,range radio link between mobile computers, mobile phones, digital camera and other portable devices.

FUTURE OF BLUETOOTH

Many think that Bluetooth is a technology that is going to be here to stay, however, just as many disagree. It is believed by ,many that there is a huge future for bluetooth. Many believed that bluetooth will be able to compete with other wireless technologies such as WiFi and it could possibly eliminates technologies such as IrDA(Infrafed Data Association)   Figure shows  where Bluetooth stands among some of the competing wireless technologies: TECHNOLOGY IDEAL APPLICATION RANGE(m) RATE(Mbps) CURRENT REQUIRED COST CONNECT TYPE Infared Device synchronization data transfer 1 16 Low 10 Low frequency Bluetooth Cable Replacement Ad Hoc 10-100 <1 Medium 10 FHSS HomeRF PCs to Consumer Goods 50 1-2 High 45 FSHH 802.11b High speed LAN 100+ 11 High 45 DSSS BLUETOOTH ADVANTAGES AND DISADVANTAGES advantages: eliminates wires and cables between both stationary and mobile phone facilitates both data and voice communication offers the possibility of ad hoc networks and delivers the ultimate synchronicity between all your personal devices it's inexpensive disadvantes: compability between Bluetooth product security relatively short range interference with other devices that may use the same frequency such as baby monitors, garage door openers, cordless phones, microwave ovens and other wireless technologies which use the same frequency mediocre data transfer rate LINKS bluetooth allow three types of data links between any two holes: an asynchronous data channel simultaneous voice channel asynchronous data chanel  INFRARED Infrared (IR) light is electromagnetic radiation with longer wavelengths than those of visible light, extending from the nominal red edge of the visible spectrum at 0.74 micrometers (µm) to 300 µm. This range of wavelengths corresponds to a frequency range of approximately 1 to 400 THz,[1] and includes most of the thermal radiation emitted by objects near room temperature. Infrared light is emitted or absorbed by molecules when they change their rotational-vibrational movements. DIFFERENT REGIONS IN THE INFRARED objects generally emit infrared radiation across a spectrum of wavelength, but somestimes only a limited region of the spectrum is of interest because sensors usually collect radiation only within a specific bandwith. Therefore, the infrared is often subdivided into smaller sections       commonly used sub-division scheme: Division Name Abbreviation Wavelength Photon Energy Characteristics Near-infrared NIR, IR-A DIN 0.75-1.4 µm 0.9-1.7 eV Defined by the water absorption, and commonly used in fiber optic telecommunication because of low attenuation losses in the SiO2 glass (silica) medium. Image intensifiers are sensitive to this area of the spectrum. Examples include night vision devices such as night vision goggles. Short-wavelength infrared SWIR, IR-B DIN 1.4-3 µm 0.4-0.9 eV Water absorption increases significantly at 1,450 nm. The 1,530 to 1,560 nm range is the dominant spectral region for long-distance telecommunications. Mid-wavelength infrared MWIR, IR-C DIN. Also called intermediate infrared (IIR) 3-8 µm 150-400 meV In guided missile technology the 3-5 µm portion of this band is the atmospheric window in which the homing heads of passive IR 'heat seeking' missiles are designed to work, homing on to the Infrared signature of the target aircraft, typically the jet engine exhaust plume Long-wavelength infrared LWIR, IR-C DIN 8–15 µm 80-150 meV This is the "thermal imaging" region, in which sensors can obtain a completely passive picture of the outside world based on thermal emissions only and requiring no external light or thermal source such as the sun, moon or infrared illuminator.Forward-looking infrared (FLIR) systems use this area of the spectrum. This region is also called the "thermal infrared." Far infrared FIR 15 - 1,000 µm 1.2-80 meV (see also far-infrared laser).

  i think that's all see yaaa...