Which modulation is used in cellphone?

GopherT

Joined Nov 23, 2012
8,012
1. I am using digital mutilmeter for measuring voltmeter.
It has 9V battery for multimeter operation.

2. My question is when I use digital multimeter for voltmeter purpose, do black probe of multimeter is shorted to its internal 9V battery or both are isolated?
which modulation is used in cellphone?
I think you are hijacking this thread about volt meters. You need to start your own thread.

By TS do you mean Terms of Service? (Usually it's abbreviated as ToS.) I don't recall anything being mentioned there about it.
No, TS is thread starter.
 

ScottWang

Joined Aug 23, 2012
6,860
By TS do you mean Terms of Service? (Usually it's abbreviated as ToS.) I don't recall anything being mentioned there about it.
Talking about the OP and TS.
The old system used OP to call an Original Poster, but the new system call that TS -- Thread Starter.
 

ScottWang

Joined Aug 23, 2012
6,860
OK, I understand now. I was trying to help, but I wasn't thinking about this thread being hijacked, which I don't want to encourage.
I have to apologize for I saw the wrong thread, and replied to you a wrong response.
When I active on this thread, but I also can view the other threads, when I tried to reply the response, I review the title and contents, but what I saw the contents were from the different thread, so I given you a wrong response.
 

tjohnson

Joined Dec 23, 2014
611
I have to apologize for I saw the wrong thread, and replied to you a wrong response.
When I active on this thread, but I also can view the other threads, when I tried to reply the response, I review the title and contents, but what I saw the contents were from the different thread, so I given you a wrong response.
That's OK. If you mean post #10, it didn't seem out of place here.
 

tjohnson

Joined Dec 23, 2014
611
I have to apologize for I saw the wrong thread, and replied to you a wrong response.
When I active on this thread, but I also can view the other threads, when I tried to reply the response, I review the title and contents, but what I saw the contents were from the different thread, so I given you a wrong response.
@ScottWang: You didn't reply in the wrong thread. The new TS (vandhana.g) had originally hijacked Vindhyachal Takniki's thread, and I replied to her there. Later, after you posted #3, a moderator moved her question (with all related posts) into a separate thread.
 

ScottWang

Joined Aug 23, 2012
6,860
@ScottWang: You didn't reply in the wrong thread. The new TS (vandhana.g) had originally hijacked Vindhyachal Takniki's thread, and I replied to her there. Later, after you posted #3, a moderator moved her question (with all related posts) into a separate thread.
Oh, I see, thanks.
I just felt very strange, before I posted the replied, obviously I did checked the title and contents, how was it happened and confused me made me to think maybe I was wrong, so now I know that.

Sometimes when separated the thread, the moderator will label an explanation, but I didn't see it this times.
 

absf

Joined Dec 29, 2010
1,942
To the OP/TS,

Let me quote the answer from Bob Wilson:

Hi Chris,

Unfortunately, your question cannot be answered so simply. Most mobile phones these days are digital. Modulation is of a general type called FSK (Frequency Shift Keying). Details depend on the type of phone network and the country it is used in. For example, in Europe and much of the rest of the world, the GSM standard is commonly used, whereas in the US the most common standard is CDMA. CDMA phones use a type of "Spread Spectrum" modulation. GMS phones use a modulation technique called GMSK (a type of continuous-phase frequency shift keying).

A good overview is here....

http://electronics.howstuffworks.com/cell-phone7.htm

...but as you will see, one thing is for sure: All mobile phone modulation schemes are vastly more complex than the simple ones you have named.

Regards,

Bob Wilson
Allen
 
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