Introduction Essay Example | Topics and Well Written Essays - 1000 words - 2

Introduction - Essay Example With this the signal is converted into a form which is compatible with the system. For analog form, A/D converter is used for the transmission of the signal, and for digital form, such a block is not required if data already exists in the digital form (Bagad and Dhotre, 2009, p.4-26). PCM – PCM or pulse-code modulation is a method based on digital encoding and are effectively used in optical fibre communications. The baseband video signal in the system is quantified and sampled. There is a series of bits that encodes the sample. The light is put on and off using binary signals. The bandwidth is required to be enhanced over the baseband method for its use. This is a good choice for optical communications, particularly when laser diode has to be utilized owing to presence of inherent nonlinearity in the source of the optics (Bandyopadhyay, 2014, p.314). PPM – PPM or pulse position modulation is used for optical communications where the code scheme involves a bit time divided into two slots. Data can either be 1 or 0. If it is 1, the pulse gets transmitted in the first bit time slot. If the data is 0, then the pulse gets generated in the second slot of the bit time. Expansion of PPM is also possible and proves to be efficient for optical communications (Alexander, 1997, p.228). Digital PPM – PPM can also be used digital transmission of information based on optical communications. It is also referred to as differential pulse position modulation. It is a variation of the PPM coding, which can transmit data irrespective of the presence of time. If delays occur in the transmission, they take reference from falling edge of the pulse that was earlier transmitted (Lazaridis, 2011). Multiple PPM and Dicode PPM – Dicode PPM and Multiple PPM are considered as the most efficient bandwidths for optical communications. The best forms of sensitivities are offered by these PPM without causing the large bandwidth of the system to increase.