Receiver Structure and Channel Statistics
Education for the receiver structure is as following. The value of a random variable W produced channel noise.How do we relate the statistics of the random variable. Characterist of the channel receiver of makes occasional errors due to the random of correlator output.
Practical Issues in Channel Bandwidth
That is, the receiver decides in favor of symbol 0 given which was actually transmitted, and vice versa. What is the probability of decision. There are some important practical issues that need attention.Channel bandwidth is a highly valuable resource. How do we choose a mod scheme that conserves bandwidth in a cost-effective manner.
The binary signal m(t) may include redundant symbols introduced in the use of channel encoding so as to provide protection against channel do we design the channel encoder in the transmitter and the channel receiver so as to come very close to Shannon's information capacity theorem.
Physically realizable manner. The locally generated carrier in the receiver of Figure 10c is physically separate the carrier source used for modulation in the transmitter. How do we synch the receiver to the transmitter with respect to both the carrier phase and timing so as to justify the use the basis of decision-making. reconstruction of the original binary signal The theoretical and practical issues raised here in rhe context of the simple communication system are addressed in the following chapters of the hoc.
Historical Notes on Communications
A preview of communications would be incomplete without a history of the subjective in this final section of this introductory chapter wc present some historical notes on communications. Each paragraph focuses on some important and related events. It is that this material will provide a sense of inspiration and motivation for the reader.
In 1837, the telegraph was perfected by Samuel Morse, a painter. What hath God wrought transmined by Morse's electric telegraph between Waste and Baltimore Maryland, in 1844, a completely revolutionary means of long-distance communications was triggered.
Morse Code and Baudot's Telegraphic Code
The telegraph is the forerunner ofthat the Morse code is a variable-length ternary code using alphabet of four symbols. A dot, a dash, a lener space, and a word space. present frequent letters, whereas long sequences represent mfrequent letters. deal for manual keying. Subsequently, Emile Baudot developed code for telegraphy m 1875.
In Baudot's telegraphic code.use with teletypewriters, each code word consists of five equal-length code each element is assigned one of nvo possible states： a mark or a space in roday's terminology.In 1864, James Clerk Maxwell formulated the electromagnetic theory predicted rhe exisrence of radio waves. the underlying set of equations bears.