Time Lag in Calls: Experiment & Confirmations

[ashishsinghal]

I was wondering how much time lag would be there if one called in a local place using mobile phone. I did a simple experiment which showed that there is a considerable time lag. Can anyone further confirm this?

 

[Fish4Fun]

There are several sources of "time lag" in digital transceivers.

1) Rx of Sound and A/D conversion and processing.
2) Transmission to Cell Tower.
3) Cell Tower processing and routing.
4) Transmission from cell tower to cell tower.
5) Second Cell Tower processing and queuing.
6) Transmission from Cell Tower.
7) Rx of Digital packet, processing and D/A conversion.

The fact that all of this typically takes place in the mS to Second time domain is astonishing!

Fish

 

[ashishsinghal]

Err...I should have told you that I am just in high school and hence have no idea of what you are talking about. I will tell you my experiment.
I called a friend, turned on a song and asked him to sing along with the song. If he hears the song after t seconds, he will start singing after t second. his voice will also come to me after t seconds. so the difference in beats that I hear directly and from him is 2t.
On casually listening the difference was about 0.5 seconds. so the lag would be about 0.25s.
Is it correct?

 

[jsgruszynski]

Err...I should have told you that I am just in high school and hence have no idea of what you are talking about. I will tell you my experiment.
I called a friend, turned on a song and asked him to sing along with the song. If he hears the song after t seconds, he will start singing after t second. his voice will also come to me after t seconds. so the difference in beats that I hear directly and from him is 2t.
On casually listening the difference was about 0.5 seconds. so the lag would be about 0.25s.
Is it correct?

The simple version: there are delays in the signal path of the phone so what you say into your phone is not instantaneously appearing on the remote phone - it takes some time. A lot of it is because though the speed of light is fast, it's not infinitely fast.

So yes, in summary, you are correct. The list given by the other respondent is simply the explicated source of each component delay that adds up to what you experience.