Phone history Thirteen or fourteen years ago, our ideas about mobile phones were very limited. The news of this object was occasionally in the papers. The phone is coming to our country too – that’s what ordinary people knew. Today that picture has completely changed. Many people who are optimistic about the success of mobile phones have not thought that this progress will happen in such a short time!
Before talking about mobile phones, first of all you need to talk about telephone and radio. Alexander Graham Bell invented the telephone in 18 at the age of 29. A year later, he founded the Bell Telephone Company and began providing telephone services on a commercial basis. The radio comes much later than the telephone. The first radio station was launched in 1922. But in a very short time it gained tremendous popularity. The biggest advantage of radio is that it goes on the radio. It is not difficult to listen to the radio from anywhere outside the house. If this facility were available on the telephone, that is, if the telephone could be used from anywhere, then there is no doubt that its usefulness would increase many times over.
Before the invention of the radio, scientists and technologists began to speculate if a mobile telephone system could be created using radio technology. In general, the difference between radio and telephone is that radio is one-way. That is, it can transmit songs, instruments, etc. with a powerful transmitter; Anyone can hear it from a great distance through a receiver. One-way publicity in this way is called ‘broadcasting’. Telephone conversations, on the other hand, are ambiguous at all times. The two can talk to each other over the telephone – without letting the world know. Considering this difference, it is not easy to match the two technologies.
It seems that if everyone has a transmitter and a receiver, then only two people can talk. That’s not wrong, but in reality there are a lot of problems. Imagine, in order to catch a station on the radio, we have to turn the tuning knob (by pressing the button in this era) to reach the frequency at which the station is broadcasting the program. Only then can the program be heard. Different radio stations broadcast their programs on different frequencies – so that one person’s program does not interfere with another’s program.
If you want to make a mobile phone with radio – you have to give a separate frequency to each subscriber. There is no such thing in the world as giving different frequencies to millions of people. In addition, there are many other problems. Have you seen the radio station transmitter – what a tall tower and how heavy it is? How do you do that? Putting a sensitive receiver near that powerful transmitter on it will make it useless in a moment.
Source: Mobile Phone Khuntinati, Mozahidul Islam Dheu, Systech Publications, Dhaka