How the receiver and transmitter automatically switch to the same channel?

Thread Starter

gggccc

Joined Aug 15, 2022
7
Hi,

We are trying to develop software for automatic frequency selection of an RF receiver and transmitter. However, there is a point we cannot understand: When the RF Transmitter makes automatic frequency selection, how will the receiver switch to that frequency? So my question here is: The transmitter must transmit the information of the selected channel to the receiver and the receiver must switch to the same channel, how can he do this?

I am a new engineer and in R&D. That's why I'm having a little trouble with this. I will be grateful if you can help me. Thanks in advance.
 

camerart

Joined Feb 25, 2013
3,054
Hi,

We are trying to develop software for automatic frequency selection of an RF receiver and transmitter. However, there is a point we cannot understand: When the RF Transmitter makes automatic frequency selection, how will the receiver switch to that frequency? So my question here is: The transmitter must transmit the information of the selected channel to the receiver and the receiver must switch to the same channel, how can he do this?

I am a new engineer and in R&D. That's why I'm having a little trouble with this. I will be grateful if you can help me. Thanks in advance.
Hi G,
The receiver must transmit it's frequency to the scanning transmitter first, so the transmitter can send the frequency that it's going to transmit on.
Camerart
 

Ramussons

Joined May 3, 2013
1,298
Hi,

We are trying to develop software for automatic frequency selection of an RF receiver and transmitter. However, there is a point we cannot understand: When the RF Transmitter makes automatic frequency selection, how will the receiver switch to that frequency? So my question here is: The transmitter must transmit the information of the selected channel to the receiver and the receiver must switch to the same channel, how can he do this?

I am a new engineer and in R&D. That's why I'm having a little trouble with this. I will be grateful if you can help me. Thanks in advance.
The technique is called polling. How this is achieved depends on the Tx-Rx architecture.
In your case, I presume it is going to be Duplex / Semi Duplex communication.
The simplest way is , as camerart mentioned, Transceiver 1 informs its Tx and Rx frequency to Transceiver 2 (which is in a scanning mode) and the link is established. (I mentioned both Tx and Rx frequencies because both are required in a Full Duplex operation).
You will need to include Authentication protocols to ensure that the correct Transceivers are paired.
 
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Ramussons

Joined May 3, 2013
1,298
If your Transceiver can be programmed to select the Tx and Rx frequencies, then you can program a micro controller to set the Rx frequencies for that band ( Tx and Rx frequencies slots are defined for each band of operation) and search for a signal. When a signal is received, you need to confirm that it is the right signal. If it is not the right one, step to the next slot. And so on...
 

camerart

Joined Feb 25, 2013
3,054
Hi,
Thinking a bit more about it and following my recent interest in Hedi Lamarr, there is another way.

She had good ideas around Channel hopping. If you've ever heard of: https://www.thefreedictionary.com/mechanical+piano she used a similar idea for channel hopping radio controlled torpedoes. Simply, if you have a roll of holed paper in the torpedo, and one at BASE, controlling/changing the frequencies in parallel, so you can have both synchronised, as long as you have predetermined channel lists.
EDITED: Name
:)
C.
 
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