JPL's Wireless Communication Reference Website

Chapter: Analog and Digital Transmission. Section: Digital Modulation.

Gaussian Minimum Shift Keying

GMSK is a popular modulation method, used in GSM, Hiperlan and DECT. It has a constant envelope, so it can be amplified using power-efficient non-linear (Class C) amplifiers.


Figure: power density spectra versus frequency normalize to user bit rate.
--- Solid line: GMSK The GMSK spectrum has a somewhat wider main lobe than BPSK, but sidelobes are much weaker. This reduces adjacent channel interference.
..... BPSK (The sinc-shaped spectrum)
- . - . QPSK (The QPSK spectrum is half a wide as the BPSK spectrum)

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JPL's Wireless Communication Reference Website © Jean-Paul M.G. Linnartz, 1997.