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Digital Modulation Schemes:

Gaussian Minimum Shift Keying(GMSK):

    It is used in GSM for making calls and in internet (you can see G symbol while browsing)


8-PSK (Octal Phase Shift Keying):

    It is used for browsing in 2G. If your mobile shows E symbol while browsing, it is using 8-PSK.


Quadrature Phase Shift Keying (QPSK):

    It is used in 3G (when your mobile shows H while browsing) and DTH like Airtel, Reliance Big TV etc.


Quadrature Amplitude Modulation (QAM):

   It is used in 3G (when your mobile shows H+ while browsing) and 4G LTE uses Orthogonal Frequency Division Multiplexing with


  1. QPSK (= 4QAM)   2 bits per symbol
  2. 16QAM   4 bits per symbol
  3. 64QAM   6 bits per symbol

     2048 QAM is also used in Microwave dish used to link BTS.


2048 QAM used in microwave dish2048 QAM used in microwave dish



Bluetooth LogoBluetooth Logo

   It uses a combination of GFSK and Phase Shift Keying modulation (PSK) with two variants, π/4-DQPSK and 8DPSK.



For details about QPSK and QAM, kindly visit