Could you please tell me if antenna is getting all the signals but the circuit decides the frequency(as u mentioned), then why there is no interference between the cellphones in the same cell, although they have the same circuits? I mean me and my friend in the same room using the same phone and calling people. I know for each mobile different frequency allocated. But hoe the phone differ thet. Dont they have the same circuit all the time?Regards,
You nailed that one: they do tune to a slightly different frequency, as a function of what the cell phone tower tells them is available. The phone have a circuit that allows them to tune to the allocated frequency. It is even capable of changing frequency when you move from a cell to a different one and are switching towers, without interrupting the flow of the communication. They also use a lot of other techniques to compress the information, divide it in packets and label them so that each set knows if the information is directed to them or not.
Mobiles phones use packet technology to transmit data. Each packet of data contains an address of the phone it is being sent to. Your phone decodes ONLY those packets addressed to it. The cell phone takes the sound waves of your voice and converts them to a digital signal. Those digital signals are then assembled into a packet of data. At the same time, the packet is given an address of the closest cell tower. All the computers attached to the cell towers determine which phone the packet is going to, and the computers on the ground route the packet through the easiest network path to the cell tower closest to the phone being called. that cell tower then transmits the packet to the cell phone. Since the packet has the address of only ONE specific phone, ONLY that phone can decode the packet. ALL of the other packets that may be floating around, even those on the same frequency, are ignored.
