Thursday 12 October 2017

Wireless Communications


Wireless communications have become synonymous with relatively short range radio communications that are able to replace wired installations. Standards including Bluetooth, Wi-Fi or IEEE 802.11, Ultra Wide Band, Zigbee and many more all fall into this category.

WiMAX - Wireless Area Metropolitan Networks


WiMAX is a broadband wireless data communications technology based around the IEE 802.16 standard providing high speed data over a wide area. The letters of WiMAX stand for Worldwide Interoperability for Microwave Access (AXess), and it is a technology for point to multipoint wireless networking.

Polarization

Polarization is an important factor for RF antennas and radio communications. Both RF antennas and electromagnetic waves are said to have a polarization. For the electromagnetic wave the polarization is effectively the plane in which the electric wave vibrates. This is important when looking at antennas because they are sensitive to Polarization, and generally only receive or transmit a signal with a particular polarization.

Near Field Communications


There is a growing number of applications where a form of very short range communications is needed. One technology that can meet this need is called Near Field Communications or NFC. While it does not have the hype of Bluetooth, Wi-Fi, WiMax, Zigbee, RFID or others, Near Field Communications (NFC) appears to be set to become a major presence in the wireless communications arena.

GPS - Global Positioning System


GPS stands for Global Positioning System, it is also sometimes called Navstar. GPS is a system that can provide a position at any point on the Earth's surface to a very high degree of accuracy. The Global Positioning System (GPS) uses 24 active Navstar satellites in orbit 11 000 miles above the surface of the Earth.

CDMA 2000 System


One of the major cell/mobile phone or cellular telecommunications technologies today is the CDMA-1/CDMA-2000 system. One of its strengths is that it has focussed on being an evolutionary technology moving from standards such as IS-95 (IS-95A and IS-95B) for CDMA-1 through to standards including IS-2000 and IS-856 for CDMA2000 1X, 1xEv, 1xEV-DO and 1xEV-DV. Currently the standard uses one standard channel under a system known as 1X RTT, although for the future three channels (3X RTT) may be used.

Ultra Wide Band Technology


UWB, or Ultra-Wide Band technology offers many advantages, especially in terms of very high data transmission rates which are well beyond those possible with currently deployed technologies such as 802.11a, b, g, WiMax and the like.

Simulation Software for Electronic Designs


The design cycles for electronics design are becoming much shorter, while at the same time circuits are becoming more complicated. This problem is one that is present in all aspects of electronics design.

PCB - Printed Circuit Board


Printed circuit boards, PCBs, form an essential part of any electronics equipment these days. The PCB design and layout forms an integral part of the design of the whole product, and it can be the key to the success of the product meeting its performance requirements in many instances.

Bluetooth Functioning


Bluetooth has now established itself in the market place enabling a variety of devices to be connected together using wireless technology. Bluetooth technology has come into its own connecting remote headsets to mobile phones, but it is also used in a huge number of other applications as well.

Tuesday 10 October 2017

Semiconductor - PN Diode


  • When electron flow in one direction in semiconductor, the holes flows in opposite direction.
  • At low temperature Semiconductor behaves like Insulator (Eg. Germanium-Ge, Silicon-Si)
  • Temperature Increases, Energy gap decreases
  • Current per unot area is called current density.