Power spectra density for line code
Digital data are stored in the form of bits, i.e: 0 and 1. The binary data is stored in memory cells usually as static charges (DC Voltage). When transmitting a series of binary bits, we need some sort of waveform to be able to send them on a specific channel. Line codes help us achieve the goal of transmitting the data over specific passband/baseband channels. Now, to be able to allocate resources such as bandwidth, power, etc, we need to know the spectral behavior of our Transmitted Signal. This signal is produced using a line code acting on a baseband signal. Therefore, we need to know the effect of the line code spectrum on the signal spectrum. Both of these spectra contribute to the final transmission spectrum, which is meant to be transmitted. Over the years, different line codes have aimed for bandwidth/power efficiency, as well as reduction/control of inter-symbol interference (ISI).