Telecommunication Principles Free Essay Example, 3250 words

If the two devices are located in distant places, this could mean that the data rate will be impaired. Similarly, short distances denote a strong network signal. With a strong signal, higher data transmission speeds will be experienced. Obstruction: obstacles to networks signals have been found to impair the data rates of the system. Walls, hills and other solid objects occurring in the way of transmission signals impair the speed of transmission. They slow down the signal and therefore reduce the transmission speed. Other obstacles may make it impossible for signals to penetrate, another setback to data rates. b) The Nyquist theorem: it is based on the assumption that noise is free. Nyquist provides the upper bound for the bit rate of a transmission system by determining the bit rate straight from the number of bits in a symbol and the bandwidth of the transmission system (assumption: 2 symbols/per cycle and first harmonic). In conclusion, it can be deducted that doubling the bandwidth doubles the data rate if only all other factors are equal. Shannon’s Theorem, on the other hand tries to determine the relationship between noise, data rate and error rate. We will write a custom essay sample on Telecommunication Principles or any topic specifically for you Only $17.96 $11.86/pageorder now This theorem is used to determine the capacity of a signal transmission system in where noise is present. The variation between the two theorems is that when the Shannon theorem gives us the upper limit, the Nyquest theorem tells us how many signal levels we require. (i) The theoretical highest bit rate C = B log2 (1 + SNR) 3000 log2 (1 + 35) = (ii) The applicable bit rate and number of signal levels First we determine the highest bit rate C = B log2 (1 + SNR) = 106 log2 (1+ 63) = 6 Mbps This is the upper limit in accordance with the Shannon formula. For higher performance and efficiency, we will use a lower value, let us say 4Mbps. The Nyquest formula will give us the levels of signal as follows 4 Mbps = 2 Ãâ€" 1 MHz Ãâ€" log2 L L = 4 L02.4 Q 2: impairments and their effects Path loss This is described as the loss in signal strength as the network signals are transmitted through space. Path loss has been identified as a major channel impairment that springs from wave expansion in the free space as a result of increased sphere. Factors that contribute to path loss include: Reflection: this is described as the change in direction of waves as a result of interaction with another surface. The result of reflection is that the wave goes back to the transmitting device (source of transmission).