What exactly is a wireless modem?

[dineshbabumm]

Hello all,


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..

Added after 43 seconds:

Also,please suggest some good sites from where i can get information about the wireless modem.. Please help me..

 

[Mr_Programmer]

Re: Wire less Modem

Hi,

you can find a complete design including theory, schematics and program at the page www.chipcon.com under application notes for CC1100 and CC1000.

Regards...

 

[shwoo]

Re: Wire less Modem

Yes, you can use FM transceiver as an FSK modem.
It doesn't have to be FM. If it is an AM transceiver, you can use it ASK modem,
which may be called On-Off-Keying (OOK).
Some precautions.
1. Understand your digital data. If it is NRZ, you might have use manchester
coding.
2. Some modulation schemes don't like long transmission of Zeros or Ones.

Hope it helps.

 

[eeklac]

Re: Wire less Modem

Yes, you are right, you need to clarify what is wireless modem.

A GSM module is most likely a real wireless modem, which can operate with your MCU or Computer through UART interface, and connected to remote system as a modem, without cabling, ie, wireless modem. However, it seems that it is too complicated to be a small project.

So, I think it is a wireless means connecting to a traditional modem connecting to the PSTN (phone network). Which you need to do is to build a wireless UART interface.

For a wireless UART interface, you need to think what kind of means you want, basically, there is RF one, and also IR one. You can easily from many IrDA chip from the market, like Vishay, TI ... And for RF, you need to check if you want to make a 2.4GHz, 9xxMHz, 4xxMHz or another frequency.

For 2.4GHz, there is many choice:
nRF24L01 from Nordic, a 2.4GHz transceiver
nRF24e1 from Nordic, a 2.4GHz transceiver plus, 8051 MCU core
CC2400 from TI (Chipcon), a 2.4GHz transceiver
CC2500 from TI (Chipcon), a 2.4GHz transceiver
CC2510 from TI (Chipcon), a 2.4GHz transceiver, plus 8051 MCU core
ATR2406 from ATMEL, a 2.4GHz transceiver
ML2724 from Microlinear, a 2.4GHz transceiver

And they also have other frequency's chipset as well, please visit them for detail.

To make the project easier, I suggested you to use the one with MCU core, nRF24e1 or CC2510, which they have AppNote (including source code) for doing similar idea, plus frequency hopping as well, which is important to avoid RF jamming.

Hope this can help.