Analog to Digital Comparison

Analog to Digital When the conversion takes place between analog and digital it becomes the base of all communication technologies. Just about all hardware uses digital so it is very important to convert analog signals into digital to perform support for hardware applications. All hardware devices are aimed to be digital. Therefore, devices in the future will not need conversion because they will already be digital. There are many examples of analog to digital like a scan picture. The analog information provided by the light present in the picture is converted to digital signal to complete the process.

The digital conversion use the means of binary coding for data transmission and output. The digital signals work only by using only two numbers known as one and zero (Analog to Digital). When users convert the signal to digital it allows plenty of data to be stored on a single device. This help save bandwidths and space. There are seven ways that signals are structured; direct conversion, ramp compare, successive approximation, delta encoded, pipeline, time stretch, and sigma delta. When the hardware uses one of those signals the destination hardware will find the best data encryption and utilization.

The most common analog to digital conversion are the digital TVs, cameras, and other video captures. The newer microcontrollers’ technologies are used to convert analog to digital by reducing the size of the chip to get a better signal. Frequency Modulation The advantages and disadvantages of frequency, and frequency modulation vary from one application to the next. However, the frequency modulation choice depends on the applications, and system requirements. Knowing the type of system as well as the requirement will help the technician choose the correct form or type frequency modulation to generate to get the required output for use.

Comparing, and contrasting Amplitude Modulation (AM) to other forms of modulation frequencies an individual will find that (AM) frequency is relatively inexpensive, minimum circuitry required for connection as well as the demodulation process. (AM) covers a larger area when compared to (FM) greatly with the aid of atmospheric conditions. A disadvantage of (AM) includes a limited amount of bandwidth where-as the bandwidth needs to be double the strength of the highest frequency, noise mixes easily at higher frequencies, and only one side of the frequency carries the signal where-as the other side has a loss of power.

Applications that normally use (AM) include radio transmission news, weather, music, aircraft communication to the aircraft tower in a very high frequency (VHF) form, and walkie-talkies for two-way communication. Frequency Modulation (FM) advantages include a stronger signal than (AM), noise control with the aid of increasing or decreasing the deviation, constant power output with no loss. The disadvantage includes cost, the demodulation process that may require knowledge of complicated circuitry. The application for (FM) includes radio communication, and some analog applications.

Phase Modulation (PM), which is analog version phase shift keying. The advantages include includes modulation to demodulation made easier when compared to (FM). (PM) is also used to determine speed or velocity. A disadvantage of (PM) will include the displacement of the original signal of more than 180 degrees will cause phase ambiguity. Applications for (PM) include boat radio communications, radio, music, and news communications. When an individual uses his or her wireless Ethernet (802. 11b) he or she does not care as to how the signal is generated just as long as it works.

Modulation Techniques Modulation is the method used to transmit and receive signals from a carrier. Different types of equipment make it possible for the signals to be used. Each piece of equipment uses different techniques but is essence offers the same results. The three most common methods by which signals are transmitted are 56K modem, asymmetrical digital subscriber line (ADSL), and Wireless Fidelity also known as Wi-Fi. Throughout the growth of the Internet, each of these processes has proven themselves to be effective ways to transmit digital signals.

However, the 56K modem has become somewhat obsolete with the emergence of Wi-Fi. The signal modulation that the 56K modem receives is provided by the telephone network. When there is no interference or problems with the network’s connection, a 56K modem has a maximum speed of 64K but will rarely come close to achieving this because of typical issues with the network. The modulation takes place by converting the digital signal that the Internet Service Provider (ISP) transmits into an analog signal that the telephone company can use.

The individual uses a modem to convert the analog signal received from the telephone company back to a digital signal. After the access to the Internet became more demanding, this process proved to be too time-consuming and ADSL emerged. ADSL uses two opposing modulation techniques that rely on Quadrature Amplitude Modulation (QAM). QAM uses a process to conserve bandwidth that was widely used by earlier modems. The first modulation technique used is the Carrierless Amplitude Phase (CAP) that was developed by AT&T.

The carrier retains no information because it is suppressed before transmission and unsuppressed after it reaches its destination. This process offer two advantages for its users, a less expensive and more flexible way of modulation and demodulation. The other modulation technique is the Discrete Multi-Tone (DMT). The DMT has been selected as the standard for ADSL. This method is a bit more complex because of the way that it separates the bandwidth into 256 channels. Each of these sub-channels uses about 4. 3125 kHz of bandwidth using the QAM process.

It also uses more low frequency channels to minimize the noise interference present during high frequency transmissions. It also uses method like Discrete Wavelet Multi-Tone to maximize the separation between the channels to assist in minimizing interference. The final modulation technique is the Wi-Fi. The Wi-Fi uses two radio transmission methods for modulation. The 802. 11b uses the process complementary coded keying (CCK) at around 11Mbps to process the signal with special codes and modulate it using Quadrature Phase Shift Keying (QPSK) (“Tutorialspoint”, 2013). The other is the 802. 1a and g type that use a 64 channel orthogonal frequency division multiplexing (OFDM) that divides the available radio band into sub-channels to send bits on each (“Tutorialspoint”, 2013). By using Binary Phase Shift Keying (BPSK), QPSK, or one of the QAM variants, the transmitter can encode the streams of bits carried on the 64 sub-channels. The receiver only uses the information that it needs to construct the information and disregard the redundant information. Sonnet SONET, or synchronous optical network (Gilmer, 2003) was designed in the 1980’s due to the break-up of AT&T.

The current technology was overwhelmed by the sheer number of new telephone companies around the country. SONET was designed to deliver T-1 and T-3 speeds for data transfers. The SONET frame is designed as an 810-byte setup utilizing nine rows of 90 bits. The remaining bits are left out of the rows to perform separate tasks for each section. SONET is still used today as a means of telecommunication as it has a superior amount of flexibility over cables, such as those utilized by Ethernet that can be only stretched a fraction of the distance achieved by fiber optic cable.

Where Ethernet maxes out at 348 feet, fiber optic cable is used at distances over a mile long, a drastic difference in usability. Conclusion It is apparent that as the popularity of the Internet increases, the technology must increase as well to meet the demands. The different conversion method used today for analog to digital has made it easier for users than in the past. The modulation techniques have improved making it possible to transmit information faster and less expensive for users. Finally, the SONET technology has propelled the industry even further with its increased range and flexibility.

References Analog to Digital. (2013 April). Retrieved from http://www. wifinotes. com/computer-hardware-components Gilmer, B. (2003). Sonet. Broadcast Engineering, 45(7), 24-24. Retrieved from http://search. proquest. com/docview/204171727? accountid=35812 Goleniewski, L. (2007). Telecommunications Essentials (2nd ed. ). Boston, MA: Pearson. Analog to Digital. (2013 april). Retrieved from http://www. wifinotes. com/computer-hardware-components Tutorialspoint. (2013). Retrieved from http://www. tutorialspoint. com/wi-fi/wifi_radio_modulation. htm