May 23, 2024


The Internet Generation

Mobile Phones – From Analog to Digital

When the first mobile phones came out of the market, many people were amazed by the advancement in its technology. Indeed, it was simply amazing for a very small piece of communication equipment to be able to send and transmit messages in voice. It was more clearly advantageous than a two way radio that were the fad during those days in which you can only call your base stations and other radio handset users linked to your channel. Most of those people who uses two way radios were hobbyist or employees of a company with a base to contact field employees to monitor their whereabouts. The advantage of a mobile phone compared to these two-way radios was the longer reaching power of a cell phone, whereas a two-way radio is limited in its range of operation.

At this stage, however, mobile phones although utilizing already the cell technology through channel reuse, was still considered as in its infant stage as the carrier it utilizes is the analog technology. But first, so that you may understand better the workings of a mobile phone, let me explain about the term channel reuse. You see, radio signals operate on a particular frequency. These radio signals, in order to be free of interference, should operate on a different frequency. Like if a certain radio frequency is on 120 MHz, another radio frequency should be in another frequency to avoid mixing signals with the radio signal that is already operating in the 120 MHz frequency. But in the case of mobile phones, many of these units operate in the same frequency, through the principle of channel reuse, thereby making the mobile phones used by many people. Channel reuse was made possible by providing limited power to every mobile phone unit and providing many cell sites or towers. Thus a mobile phone can relay and receive signal only to the nearest cell site or tower nearest to it and not affect another cell tower on another location, making it possible for other cell phones on the same channel to send and receive signals on other cell sites or towers without interference.

Now that you have a good idea how cell phone operates, let us go back to the first carrier used by mobile phones which is the Analog system of carrying radio signals. This kind of radio signals carriers are the up and down frequencies of radio transmissions that were used in all forms of radio messages before the advent of digital technology. A very good example of these signals can be seen on hospital operating rooms that are usually in TV and movies depicting the near death of an individual as shown by the up and down movement of a moving light on a monitor graph. The up and down light that you see moving is an analog signal frequency, depicting the sound of a patient’s heartbeat.

When digital signals became available to be used in radio communications, it was found out that the system of channel reuse employed on mobile phones is more adapted to using the digital system of carrying signals as digital are not susceptible to interference unlike analog. Thus, telecommunication companies soon begun to reconstruct their signaling system to adapt to the digital system of signal delivery in mobile phones.

It was at this stage that a communication company in England was able to develop a system of digital communication known as the Short Messaging Service or SMS for use on cell phones using the digital system of signal delivery. By the way, SMS can only be made possible with a digital carrier but never possible in the old system that was the analog carrier. The development of the SMS or text massaging capability of mobile phones was actually designed for use by the deaf and mute segment of the community. But now we know what happened to this kind of communication intended for the deaf and mute.