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Name: Chris
Status: Student
Grade: 9-12
Location: Outside U.S.
Country: Singapore
Date: January 2009
Question:
What type of modulation do mobile phones use? Is it Frequency Modulation, Amplitude Modulation, or Pulse Modulation?


Replies:
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


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