Data transmission medium
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The document discusses data transmission between a transmitter and a receiver using both guided mediums (like twisted pair and optical fiber) and unguided mediums (such as air and vacuum). It covers key transmission concepts including peak amplitude, frequency, phase, and how signal strength can diminish over distance, emphasizing the advantages of digital transmission. To counteract signal degradation, the use of amplifiers, repeaters, and techniques to equalize attenuation across frequencies is recommended.
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Data transmission medium
- 3. Data transmission occurs between a transmitter & receiver via some medium Guided medium • E.g. twisted pair, coaxial cable, optical fiber Transmission Terminology Unguided / Wireless medium • E.g. air, water, vacuum Transmission Terminology
- 9. Peak amplitude (A) Maximum strength of signal volts Frequency (f) Rate of change of signal Hertz (Hz) or cycles per second Period = time for one repetition (T) T = 1/f Phase () Relative position in time
- 11. Is distance occupied by one cycle Between two points of corresponding phase in two consecutive cycles Assuming signal velocity v have = VT Or equivalently f = v Especially when v=c o c = 3*108 ms-1 (speed of light in free space)
- 19. Cheaper Less susceptible to noise But greater attenuation Digital now preferred choice
- 21. Where signal strength falls off with distance Depends on medium Received signal strength must be: Strong enough to be detected Sufficiently higher than noise to receive without error So increase strength using amplifiers/repeaters Is also an increasing function of frequency So equalize attenuation across band of frequencies used E.g. using loading coils or amplifiers
- 25. By Vishal Kumar Class = 9th- E Roll no.=39