Analog and Digital Comparison Paper
Amanda Dyer, Derick Campos, Jesse Ford, Mehran Gerami, Nicolas Monteiro, Wendell Taylor
October 15, 2015
Richard Swafford, Jr.
Analog and Digital Technology: A Comparison
Analog and digital are two different types of signals used to transmit audio or visual information from one place to another. Analog signals are continuous, meaning that there are no breaks or interruptions and digital signals are not continuous, they use specific values to represent information (Strickland, 2008). Analog transmissions are sent via electronic pulses of varying amplitude, while digital transmissions are converted into binary format to represent two ...view middle of the document...
The next step is understanding how the signals (wave forms) can vary and the advantages and disadvantages of those wave forms modulation types, in either a transmitted or received signal.
Two types of modulations are Amplitude Modulation (AM) and Frequency Modulation (FM). The textbook defines ‘amplitude’ as a measure of the height of the wave (signal), which indicates the strength, or power, of the signal, and ‘frequency’ as the number of oscillations per second of an electromagnetic wave (Goleniewski, 2007). AM signals are known to modulate in amplitude by the signal that is to be transmitted. FM signals are known to modulate in frequency by the signal that is to be transmitted. Although it is cheaper, AM has poorer sound quality and in FM, it is much more reliable security wise because the signal can be encrypted (Poole, 2015).
These are just a few of the advantages and disadvantages, and depending on the transmission modulations and signals being used, meeting the endpoint can be determined from these factors, as far as clarity of signal goes for audio and video.
Phase Modulation (PM)
Phase Modulation (PM) is the modulation technique in which carrier phase varies based on analog baseband information signal to be transmitted using wireless device. Phase modulation is referred as indirect frequency modulation due to the fact that phase modulation produces frequency modulation. The advantages and disadvantages of phase modulator differ from other modulators. For example, one advantage is the phase modulation & demodulation can be easily compared to frequency modulation. In other words, if one understands frequency modulation they should have no problem understanding phase modulation. Another advantage of phase modulations is that it is used in determining velocity of moving targets by extracting Doppler information. Doppler information refers to the Doppler Effect which is the change in frequency of a wave. Doppler information needs a stable carrier, which is possible in phase modulation but not in frequency modulation. On the other hand, here are some disadvantages of phase modulation. One disadvantage of phase modulation is that phase ambiguity comes into effect if you go pass its modulation index (180 degree). This means the frequency output signal becomes inverted in relation to the input. Another disadvantage is that you need frequency multiplier to increase phase modulation index.
Quadrature Amplitude Modulation (QAM)
Quadrature Amplitude Modulation, also known as QAM is a method of combining two amplitude-modulated (AM) signals into a single channel, thereby doubling the effective bandwidth. One of its advantages is its capability to increase the efficiency of transmission due to the use of both amplitude, and phase variations in radio communications. However, its disadvantages are that in order to move the signal to a different decision point, the lower levels of noise are needed. This noise may present a problem...