Demystifying Voice & Data -- Part 2
In part one, we discussed analog, switch and multiplexing. In this article we will try to demystify the topic of digital.
While Analog has been effectively used for years, its use is limited. Specifically, in comparison to digital, analog is very inefficient and takes up a lot of resources. With the advent and improvement of digital computers, the cost of processing digital diminishes, while analog becomes more expensive (by comparison). With better transmission techniques (fiber, wireless, etc.), the world of digital is a fait accompli.
The following are some familiar and real world examples of the differences between analog and digital:
ANALOG VS. DIGITAL EXAMPLE #1 -- An analog device used for counting is an abacus. Imagine adding up 1,000 numbers using an abacus. Even an expert would take several minutes to accomplish this task. However, a computer can perform this in a fraction of a second. What is the likelihood of any errors with the Abacus? What if you were adding 10,000 numbers? What about adding 100,000 numbers? The digital advantage is speed.
ANALOG VS. DIGITAL EXAMPLE #2 -- When you call your bank, you are asked to provide your account number. You may either provide this information via the key pad (digital) or speak the individual numbers (analog). The information (account number) is the same, but the means of how it is transmitted is different. The value of digital is clear and unambiguous. Analog (voice) is more problematic. What if the speaker has a heavy accent and the numbers they speak are difficult to understand? The digital advantage in this scenario is clarity.
ANALOG VS. DIGITAL EXAMPLE #3 – Almost anyone is familiar with records, turntables, and stereo speakers. When you play a record, the record player stylus converts the record grooves into voice waves (music), which is then transmitted and played over the speakers. Since there is wear and tear of the stylus on the record, over time, the recording will degrade. A compact disk (CD) is the digital equivalent of a record. Since the CD contains the numeric representation of the record, there is no wear and tear. In this scenario, the digital advantage is better and longer lasting quality.
ANALOG VS. DIGITAL EXAMPLE #4 - Anyone over 35 is familiar with VCRs (video cassette recorders). The VCR reads the VHS (video home system) tape and converts it to an audio and video signal. VHS tapes are now viewed as bulky with poorer quality. The DVD (digital video disc), replaced VHS tapes. Imagine if Netflix started by sending VHS tapes via U.S. Postal Service. Not only would the packages be bigger (more expensive), tapes are more fragile, which would lead to more breakage. Even something as mundane as the size of your mailbox is an issue. If you live in an apartment, would a VHS tape (or two or three VHS tapes) fit in your mail box? Would two or three DVDs fit? The digital advantage in this case is you have more content in a more compact format.
ANALOG VS. DIGITAL EXAMPLE #5 – You may recall the analog to digital conversion back in 2009. On June 12, 2009, the major TV broadcasters were required to shut down analog signals. Consumers who used old style (analog) antennas were given new digital antennas, which converted digital signals to analog. The reason for this change was to "free up" the bandwidth for other purposes such as wireless data transmission. In this case, the digital advantage was a more efficient use of resources.
Your voice calls are digitized (converted) into "numbers." How does this work? In simplistic terms, think of yourself as a computer. You hear someone speak and you transcribe what you hear. For example, you hear a speaker say, "the quick brown fox jumped over the lazy dog," and you put it in text. You converted voice (analog) waves into text (digital). Later on, you read the text (digital) and convert it back to analog (speak the words).
CONVERTING TEXT (CHARACTERS) TO DIGITAL (0's and 1's)
You may recall that computers work with 0's and 1's (on or off), and this is the smallest unit of measurement (bit). A byte is comprised of eight bits and can represent up to 256 "characters." As an example; "The Quick Brown ..." is converted as follows:
T converted to --> 01010100
h converted to --> 01101000
e converted to --> 01100101
Q converted to --> 01010001
u converted to --> 01110101
i converted to --> 01001001
c converted to --> 01100011
k converted to --> 01101011
There are different characters (bytes) for upper and lower case:
B converted to --> 01000010 (upper case)
b converted to --> 01100010 (lower case)
There are different characters (bytes) for numbers:
0 converted to --> 00110000
1 converted to --> 00110001
2 converted to --> 00110010
5 converted to --> 00110101
7 converted to --> 00110111
9 converted to --> 00111001
There are different characters (bytes) for special characters:
* converted to --> 00101010
@ converted to --> 01000000
" converted to --> 00100010
The important point to remember is not how your voice is converted to digital; rather, that your voice is routinely "digitized," which opens up a world of possibilities.
"SCTC Perspectives" is written by members of the Society of Communications Technology Consultants, an international organization of independent information and communication technology professionals serving clients in all business sectors and government worldwide.