Question

How does the power of a message signal matter in its accurate transmission and reception?

Answer 1

In time domain a signal can be considered as a continuous wave form and it can be specified by respective frequency components and its respective amplitudes. The amplitude of a signal component is used to calculate signal power. Signal power is an important aspect when it comes to evaluation of the quality of signal in presence of noise. A high ratio of signal power to noise power results in clear and quality signal, on the other hand, low ratio of signal power to noise power results in poor quality signal.

According to Shannon theorem, capacity of a signal is directly proportional to bandwidth of the respective signal. For example, consider a water pipe, amount of water flowing through the pipe is directly proportional to width of water pipe. Wider the pipe, more the water flow.

Another aspect of Shannon theorem shows that the signal power is proportional to increase in noise power, when we see this in terms of pipe, in order to carry more amount of water(information) pipe must be cleaner. This means that transmission of signal becomes faster.

On the other hand, lower the signal power as compared to noise power, dirtier the channel. This results in decreasing reliability of communication i.e. communication becomes less reliable. This shows us the adequate need of power of a signal message in its accurate transmission and reception. In general terms, one can say that , we have to speak slowly to get a message across the channel if the channel is not clean enough.

Shannon theorem also implies that, any channel can be used for communication as long as signal power exists.