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Wireless Modem

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dineshbabumm

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I was asked to design a wireless modem for a lab experiment.. But i am not sure what exactly it is.. Can a Fm transceiever also be called as a wireless modem?? What exactly is wire less modem?? Please,any one of you help me..

Also,please suggest some good sites from where i can get information about the wireless modem.. Please help me..
 
A modem is a box that lets a computer sends data to another computer with a modem. Wireless means instead of needing wires it does it with radio waves.
 
A modem is a device that lets the computer, which talks in digital one's and zero's, send and receive data with another computer through a medium that is analog. Mediums that are analog include the telephone line, the radio spectrum, light beams and pretty much almost anything actually. So, a modem is an interface device. If someone has asked you to design a wireless modem, they want you to make a device that lets one computer talk to another without using wires.

There are many ways to do this. But first, there is a question. Since modems are used to let two computers talk to each other, it is essential that each of the two computers have its own modem. Are you supposed to design two modems or just one? Are you supposed to build one, or two, or is this just a theoretical exercise? If just one, is it supposed to talk to another modem that someone else has built? What I'm getting at is the question; are you supposed to make a modem that works to an industry standard or can you invent your own method?

If you can invent your own method for both modems, you can choose to make them wireless by using radio waves, or by using light, or by using sound as the transmission medium. Most of the time, when people use the term "wireless modem" they mean the type that uses radio waves.

It is certainly possible for an FM transceiver to be made into a wireless modem. I spent 20 years of my career doing exactly that. This is a relatively complex thing to do unless your goals are modest. For example, if you just want to transfer at a slow rate, like 300 bps, then you can build a modem that puts out sounds which then tie into the microphone and speaker interfaces of the transceiver. For example, you can define one sound (or tone) to mean a logic one, and another sound to mean a logic zero. This is the most basic kind of radio modem and possibly the easiest to build. Back in the early days of personal computing there was a defined standard for this type of modem that was called Bell 103. It is likely that you can still find chips that implement such a thing, which would make your job easier.
 
RadioRon said:
A modem is a device that lets the computer, which talks in digital one's and zero's, send and receive data with another computer through a medium that is analog. Mediums that are analog include the telephone line, the radio spectrum, light beams and pretty much almost anything actually. So, a modem is an interface device. If someone has asked you to design a wireless modem, they want you to make a device that lets one computer talk to another without using wires.

There are many ways to do this. But first, there is a question. Since modems are used to let two computers talk to each other, it is essential that each of the two computers have its own modem. Are you supposed to design two modems or just one? Are you supposed to build one, or two, or is this just a theoretical exercise? If just one, is it supposed to talk to another modem that someone else has built? What I'm getting at is the question; are you supposed to make a modem that works to an industry standard or can you invent your own method?

If you can invent your own method for both modems, you can choose to make them wireless by using radio waves, or by using light, or by using sound as the transmission medium. Most of the time, when people use the term "wireless modem" they mean the type that uses radio waves.

It is certainly possible for an FM transceiver to be made into a wireless modem. I spent 20 years of my career doing exactly that. This is a relatively complex thing to do unless your goals are modest. For example, if you just want to transfer at a slow rate, like 300 bps, then you can build a modem that puts out sounds which then tie into the microphone and speaker interfaces of the transceiver. For example, you can define one sound (or tone) to mean a logic one, and another sound to mean a logic zero. This is the most basic kind of radio modem and possibly the easiest to build. Back in the early days of personal computing there was a defined standard for this type of modem that was called Bell 103. It is likely that you can still find chips that implement such a thing, which would make your job easier.

Thank you very much for your reply..

I am doing my Under graduate engineering only.. This is one of my exercise in system design lab.. So it will be a modest experiment only.. Just a working model.. Effeciency,industrial standards is not necessary..

We will be given a board and we got to apply our knowledge and construct a wireless model using our logic.. We were clearly told that it is a wireless modem.. Developing a modem itself is some what big task for UG level.. But,wireless,we find quite difficult..

I constructed one DTMF transmitter,but it had lot of noise.. I think,bit rate won't be a problem now.. Even low bit rate,but a working model..
 
You might try googling for "terminal node controller", this is what radio amateurs use for packet radio - there are various DIY designs on the net, and they are basically wireless modems.
 
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