WIRELESS PROJECT

[netvinod]

hi, have anyone ever tried to impleented half duplex communication using two Tx/Rx pairs of the same frequency... ??? what are the practical issues ... i want to know that

 

[JimB]

What you are describing is quite a normal comms scheme. Using a single frequency for half-duplex is ok. (Note, what computer people call "half duplex", radio people call "simplex").

The practical issues are:

The transmitters should be OFF until required to transmit, the receivers should both be ON.

When one end wants to transmit data:
Turn on the transmitter
Wait for the transmitter to settle
Send the data
Turn off the transmitter
Listen for a reply

If you are using a computer to send the data (RS232), use RTS to turn on the transmitter, then wait for the transmitter to set CTS to tell you it is transmitting. (this assumes that there is a modem of some sort in the transmitter/receiver).

Depending on the power output of the transmitter, you will need to implement some form of antenna switching when going from recieve to transmit and back to receive.

If it is just a low power short range system separate antennas for the transmitter and receiver will probably be ok.

JimB

 

[mstechca]

I'm both a computer and electronics person.

To me, simplex is a 1-way only communication. TV's and radios can be considered simplex.

Half duplex for radio work (like the last guy said) is quite common. Walkie talkies are a perfect example of half duplex. Half duplex is where two way communication exists, but data is sent only in one direction. To me, half duplex is a pain because if you wanted to argue with the other person, you can't. LOL

Full duplex is the best and faster. A telephone conversation can qualify for full duplex because in full duplex, you can send and receive data anytime you want, and you can send and receive at the same time too.