Tag: Data Communications

Digital to Digital Line Coding Line coding dijital sinyali dijital sinyale çevirme işlemidir. Signal Element VS. Data Element Data Rate VS. Signal Rate Baseline Wandering – In decoding a digital signal, the receiver calculates a running average of the received signal power. This average is called the baseline.-The incoming signal power is evaluated against this…

Radio signals may propogate from transmitter to receiver in 3 main different modes Ground Wave Propogation Sky Wave Propogation Line of Sight Propagation Refraction – bending of microwaves by the atmosphere§ Velocity of electromagnetic wave is a function of thedensity of the medium§ When wave changes medium, speed changes§ Wave bends at the boundary between…

Twisted-pair Cable Why is there twisting in twisted-pair cables? To prevent noise, signal interference and crosstalk during transmissions, twisting is introduced into conducting cables. Twisting reduces the strength of noise signals and cancels out external waves by moving a part of the noise in the direction of the signal and another part in the opposite direction. Since…

Antennas Radiation pattern In the field of antenna design the term radiation pattern (or antenna pattern or far-field pattern) refers to the directional (angular) dependence of the strength of the radio waves from the antenna or other source. Dipol In radio and telecommunications a dipole antenna or doublet is the simplest and most widely used class of antenna. The dipole is any one of a class of antennas producing a radiation pattern approximating that…

Bandwith Ex: A network with a bandwidth of 10 Mbps can pass only average of 12’000 frames per minute with each frame carrying an average of 10’000 bits. What is throughput of this network? Latency(Delay) Ex: What are the propagation time and transmission time for a 25kB message if the bandwidth is 16 bps? Assume…

Thermal Noise Thermal Noise in watts present in a bw(?) of B Hz: indecibel watts: Example: Give a receiver with an effective noise temp of 294K and a 10MHz bandwith what is the thermal noise level at this receiver’s output? DATA RATE Bir saniyede ne kadar bit yollanabildiği 3 faktöre bağlı Nyquist Channel Capacity (noiseless…

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